I 111 



LIBRARY OF CONGRESS 



029 827 665 3 



TJ 303 
.C2 fl4 
1919 
Copy 1 



TENTATIVE REVISED 



Boiler Safety Orders 



Issued by the 

Industrial Accident Commission 

of the 

State of California 



Public hearings on Tentative Revised Boiler Safety Orders will be 
held as follows: In Room 307 Underwood Building, 525 Market Street, 
San Francisco, on Thursday, August 19, 1920, at 10:00 o'clock a.m. 
in Room 405 Union League Building, Los Angeles, on Tuesday, 
August 24, 1920, at 10:00 o'clock a.m. 



CAML'ORNIA STATE PRINTING OFFICB 

SACRAMENTO 

19 19 



48403 






INDUSTRIAL ACCIDENT COMMISSION 
OF ThTE STATE OF CALIFORNIA 



525 Market Street, San Francisco 

423 Un/ion League Building, Los Angeles 



WILL J. FRENCH. 
A. J. PILLSBURY, 
A. H. NAFTZGEE, 

Commissioners. 



H. M. WOLFLIN. 

Superintendent of Safety. 



n^ •f ». 

AUQ 2/ 1920 




v> 



SUMMARY OF THE SAFETY PROVISIONS 

,i\ of the 

WORKMEN'S COMPENSATION, INSURANCE AND 
SAFETY ACT OF 1917. 

(Chapter 586 of the Laws of 1917, as amended by chapter 471 of the 

Laws of 1919.) 

[Sections 33 to 54 inclusive, of the Workmen's Compensation, Insurance 
and Safety Act, give the Industrial Accident Commission p'ower to make and 
enforce safety orders, rules and regulations, to prescribe safety devices, and to 
fix safety standards. It also empowers the Commission to appoint advisors 
who shall, without compensation, assist the Commission in establishing stand- 
ards of safety. The Commission may adopt and incorporate in its general 
orders such safety recommendations as it may receive from such advisors.] 

The Commission, carrying out its plan of obtaining the best 
practical ideas to incorporate in its Safety Orders, asked various 
interests to serve on committees to draft Boiler Safet}^ Orders. 
These committees were named after consultation with the General 
Safety Orders committees, which were organized in San Francisco 
and Los Angeles, and which assisted the Commission in the prep- 
aration of General Safety Orders which went into effect January 1, 
1916. 

As with the General Safety Orders committees, one committee 
on Boiler Orders met in San Francisco, the other in Los Angeles. 

SAN FRANCISCO COMMITTEE ON BOILER SAFETY ORDERS. 

George A. Armes (Chairman), representing the Union Iron Works, as manu- 
facturers of Boilers. 

(Frederick Birdsall, alternate to Mr. Armes.) 

J. B. Warner (Vice-Chairmau), representing the Hartford Steam Boiler 
Inspection and Insurance Compan3^ 

E. R. KiLLGORE, representing the Standard Oil Company, as users of Boilers. 

D. P. Delury, representing the Board of Public Works of San Francisco. 

M. J. McGuiEE, representing the Boilermakers and Shipfitters Union, 

W. R. TowNE, representing the International Union of Steam and Operating 
Engineers, Local No. 64. 

Chas. a. Smith, representing the California Metal Trades Association. 

John Mitchell, representing the International Union of Steam and Operating 
Engineers, Local No. 507. 

R. L. Hemingway, Safety Engineer, Industrial Accident Commission. 

John R. Brownell, (Secretary), formerly Superintendent of Safety, Indus- 
trial Accident Commission. 



LOS ANGELES COMMITTEE ON BOILER SAFETY ORDERS. 

Feed J. Fischer (Chairman), representing the National Association of Steam 

Engineers No. 2, 
H. L. Dgolittle ( Vice-Chairman), representing the Southern California Edison 

Company. 
J. J. Malone, representing the Hartford Steam Boiler Inspection and Insurance 

Company. 
William H. Carter, Chief City-Boiler and Elevator Inspector, representing the 

City of Los Angeles. 
S. M. Walker, representing the Pioneer Boiler and Machine Works. 
J. L. Glennon, representing the Fidelity and Casualty ..Company of New York. 
M. E. Carroll, representing the Steam aud*.Operating Engineers No. 72. 
E. C. Jordan, representing the 'Firemen's Local No. 220. 
11. Ij. Boyd (Secretary), Safety Engineer, Industrial Accident Commission. 

REVISION COMMITTEES. 

(San Francisco.) 

J. E. Woodbridge, representing the Sierra and San Francisco Power Company, 

elected Chairman of the Committee. 
0. H. Delany, representing the Pacific Gas and Electric Company. 
V. R. Hughes, representing the Pacific Gas and Electric Company and 

Southern Pacific Company. 
H. J. Cross, of Chas. C. Moore and Company, representing the San Francisco 

Machinery Dealers Association. 
W. W. Peed, Hammond Lumber Company, rei)resenting the Pine and Redwood 

Associations. 
J. I-I. Petherick, representing the Fidelity and Casualty Company of New 

York. 
John Kilpatrick, representing the Ocean Accident and Guarantee Corporation. 
E. B. Partridge, representing the Standard, Associated, Shell and Union Oil 

Companies. 
J. B. Warner, representing the Royal, Travelers, Hartford and Maryland 

Insurance Companies. 
Wm. R. Towne, representing the International Union of Steam and Operating 

Engineers, Local No. G4, San Francisco. 
J. J. Tracy, representing the International Union of Steam and Operating 

Engineers, Local No. 507, Oakland. 
R. L. Hemingway, representing the Industrial Accident Commission. 
John R. Brownell, formerly Superintendent of Safety, Industrial Accident 

Commission, elected Secretary of the Committee. 



(Los Angeles.) 

Feed J. Fischer, representing National Association of Stationary Engineers, 

California No. 2, elected Chairman of the Committee. 
R. J. C. Wood, representing Southern California Edison Company. 
Ralph J. Reed, representing Chamber of Mines and Oils. 
E. R. Winnett, representing Los Angeles and Salt Lake Railway. 
J. T. Johnston, representing Santa Fe Oil Division. 
J. T. Bliss, representing Merchants and Manufacturers Association. 
T. C. Royer, representing Merchants and Manufacturers Association. 
J. J. Bacchus, representing Board of Public Works, City of Los Angeles. 
Feed C. Marsh, rep-resenting Steam Fitters and Stationary Engineers Union, 

Local No. 72. 
A. W. Remnitz, representing Llewellyn Iron Works. 

Guy C. Boynton, alternate II. S. Hitchcock, representing Baker Iron Works. 
R. L. Hemingway, representing Industrial Accident Commission. 
A. Wade, representing Industrial Accident Commission. 
John R. Brownell, formerly representing Industrial Accident Commission, 

elected Secretary of the Committee. 



BOILER SAFETY ORDERS. 

Order 800. Inspection of steam boilers. 

CHAPTER 202. 

Ail act to pj-ovide for the periodical inspection of steam hoilers, 
with certain exceptions, operated in this state; requiring a 
permit, to he issued hy the industrial accident commission, for 
the operation of such hoilers; making it a misdemeanor to oper- 
ate such boilers ivithout such permit; and allowing an injunc- 
tion against such operation witJiout such permit where danger- 
ous to the life or safety of employees; providing for a hearing 
before the industrial accident commission prior to refusal of a 
permit; providing for the determination of competency of 
inspectors making such inspections and requiring reports of 
inspections; and prescribing maximum fees for such 
inspections. 

[Approved May 9, 1917; Stats. 1917, p. 297.] 

The people of the State of California do enact as follows: 

Section 1. Xo steam boiler, unless exempted in the following 
section, shall be operated in the State of California unless there 
shall have been issued for the operation of such boiler a permit, as 
hereinafter provided, and unles.s such permit shall remain in full 
force and effect. Such permit must be posted under glass in a 
conspicuous place on or near the boiler covered by it. The viola- 
tion of this section by any person owning or having the custody, 
management or operation of such boiler without such permit 
shall be a misdemeanor and the operation of such boiler without 
such permit shall constitute a separate offense for each day that 
it shall be so operated; provided, that no prosecution shall be 
maintained where the issuance or renewal of such permit shall have 
been recjuested and shall remain unacted upon. If the operation 
of such boiler without such permit shall constitute a serious menace 
to the lives or safety of persons employed about it, the industrial 
accident commission, a commissioner or any safety inspector 
thereof, or any person affected thereby, may apply to the superior 
court of the county in which such boiler is situated for an injunc- 
tion restraining the operation of said boiler until such condition 
shall be corrected or such permit secured. The certification of 
the industrial accident commission that no permit exists for the 
operation of such boiler, and the affidavit of any such inspector 
that its operation constitutes a menace to the life or safety of 
any person or persons employed about it, shall be sufficient proof 
to warrant the immediate granting of a temporary restraining 
order. 

Sec. 2. The following boilers are exempt from the provisions 
of this act : 

(1) Boilers under the jurisdiction or inspection of the United 
States government, and all other boilers operated by employers 



VI TENTATIVE BOILER SAFETY ORDERS. 

not subject to the workmen's compensation, insurance and safety 
act of 1917, and acts amendatory thereof. 

(2) Boilers of twelve horsepower or less, on which the pressure 
does not exceed fifteen pounds per square inch. 

(3) Automobile boilers and boilers on road motor vehicles. 
Sec. 3. The industrial accident commission shall cause to be 

inspected, internally and externally, not less frequently than once 
in each year, every steam boiler subject to the provisions of this act. 
If such boiler be found upon such inspection to be in a safe condi- 
tion for operation, a permit shall be issued by the commission for 
its operation for not longer than one year, which shall be the permit 
referred to in section one of this act. If any such inspection shall 
show such boiler to be in an unsafe or dangerous condition, the 
commission, or a commissioner, may issue a preliminary order 
requiring such repairs or alterations to be made to such boiler as 
may be necessary to render it safe, and may order the use of such 
boiler discontinued until such repairs or alterations are made or 
such dangerous or unsafe conditions are remedied. Unless such 
preliminary order be complied with, a hearing before the commis- 
sion, a commissioner or referee of such commission, shall be allowed, 
upon recjuest, at which the owner, operator or other person in 
charge of said boiler shall have opportunity to appear and show 
cause why he should not comply with said order. If it shall there- 
after appear to the commission that such boiler is unsafe and that 
the recjuirements contained in said preliminary order should be 
complied with, or that other things should be done to make said 
boiler safe, the commission may order or confirm the withholding 
of the permit to operate said boiler, and may make such require- 
ments as it deems proper for the repair or alteration of said boiler, 
or the correction of such dangerous and unsafe conditions. Such 
order may thereafter be reheard by the commission, or reviewed by 
the courts, in the manner specified by the workmen's compensation 
insurance and safety act of 1917 for safety orders, and not other- 
wise. It may also, in its discretion, issue and renew temporary 
permits for not to exceed thirty days each, pending the making of 
replacements or repairs. Nothing contained in this act shall be 
construed to limit the authorit}^ of the commission to prescribe or 
enforce general or special safety orders. 

Sec. 4. The commission may cause the inspection herein pro- 
vided for to be made either by its safety inspectors or by any quali- 
fied boiler inspector employed by any county, city and county, city, 
or insurance company, or by any boiler inspector employed by any 
person or corporation for the purpose of testing his own boilers 
only; provided, that such persons making inspections other than 
such safety inspectors shall first secure from the said industrial 
accident commission a certificate of competency to make such 
inspections. The industrial accident commission is hereby vested 



TENTATIVE BOII.ER SAFETY ORDERS. Vll 

with full power and authority to determine the competency of any 
applicants for such certificate, either by examination or by other 
satisfactory proof of qualifications. The commission may rescind 
at any time, upon good cause being shown therefor, any certificate 
of competency issued by it to a boiler inspector, or may at any time, 
upon good cause being shown therefor, and after notice and an 
opportunity to be heard, revoke any permit to operate such steam 
boiler. 

Sec. 5. The industrial accident commission shall fix and collect 
fees for the inspection of steam boilers covered by this act, not 
exceeding two dollars and fifty cents for each external inspection 
and seven dollars and fifty cents for each internal inspection per 
annum. Such fees must be paid before the issuance of any permit 
to operate the said boiler. No fee shall be charged by the industrial 
accident commission where an inspection, as herein provided, has 
been made by an inspector holding a certificate of competency from 
said commission and employed by any county, city and county, 
city, insurance company, or by any person or corporation for the 
purpose of testing his own boilers only. All fees collected by the 
commission under this act shall be paid into the accident prevention 
fund. 

Sec. 6. Every inspector so certified shall forward to the com- 
mission on the forms provided by it, Avithin twenty-one days after 
such inspection is made, a report of such inspection, in default of 
which the certificate of competency may be canceled. 

(Z>) The owner or user of a boiler or boilers herein required to be 
inspected shall, after fourteen (14) days notice, prepare the boiler 
for internal inspection, or hydrostatic pressure test, if necessary. 
To prepare a boiler for internal inspection, the water shall be 
drawn off and the boiler thoroughly washed. All manhole and 
handhole covers,* and wash-out plugs in boilers and water column 
connections shall be removed, and the furnace and combustion 
chamber thoroughly cooled and cleaned. Enough of the brickwork 
shall be removed to determine the condition of the boiler, furnace 
or other parts, at each annual inspection. 

The steam gauge shall be removed for testing. 

(c) If it is found that steam or hot w^ater is leaking into the 
boiler, the source of such leakage shall be disconnected and so 
drained as to cut out such steam or hot water from the boiler to 
be inspected. 

(d) If the boiler is jacketed so that the longitudinal seams of 
shells, drums or domes can not be seen, and if it can not other- 

*As a rule, in watertube boilers, it will be sufficient if such as are necessary 
of the two lower rows of tube covers be removed. 



Vlll TENTATIVE BOILER SAFETY ORDERS. 

wise be determined, enough of the jacketing, setting wall or other 
covering shall be removed so that the size and pitch of the rivets 
and such other data as may be necessary can be determined at first 
data inspection. 

(e) In preparing a boiler for hydrostatic test, the boiler shall be 
filled with water to the stop valve. If. the boiler to be tested is 
connected with other boilers that are under steam pressure, such 
connections shall be blanked off unless there be double stop valves 
on all connecting pipes, with an open drain between. 

t(/) Boilers of locomotives shall have the dome cap, stand pipe 
and throttle box, and where necessary a sufficient number of tubes, 
removed to permit of a thorough internal examination of the boiler 
at least once in five years. 

The lagging and saddle tank, if any, shall also be removed at 
least once in five years to permit of proper external examination. 

These periods may be extended by the industrial accident com- 
mission upon written application, if an investigation shows that 
conditions warrant it. 

Both the above inspections must be made within three years from 
October 1, 1920, unless such inspections have been made between 
January 1, 1917, and October 1, 1920. 
Order 801. Insurance inspections. 

As provided in chapter 202, Laws of 1917, all boilers subject to 
periodic inspection of insurance companies authorized to insure 
boilers in the State of California shall be exempt from regular 
annual inspection by the Industrial Accident Commission on the 
following conditions : 

(a) The insurance companies' regulations shall conform with 
the herein orders. . 

(5) The insurance companies' inspectors who inspect boilers 
operated in this State shall hold certificates of competency issued 
by the Industrial Accident Commission, as hereinafter provided. 

(c) Reports of all inspections shall conform to the requirements 
of this Commission, and shall be made upon the forms provided. 

(d) A copy of all annual reports shall be forwarded to this 
Commission within twenty-one (21) days after the inspection is 
made, on the forms provided. 

(e) Insurance companies whose inspectors hold certificates of 
competency shall immediately report to this Commission the name 

tindicates revision, 1920, by the Industrial Accident Commission of tlie State 
of California. 



TENTATIVE BOILER SAFETY ORDERS. IX 

of the owner or operator, and the location of ever}^ boiler on which 
insLirance has been refused, cancelled or discontinued, giving the 
reasons therefor. 

Order 802. Special inspections. 

{a) As provided in chapter 202, Laws of 1917, steam boilers 
within the regular corporate limits of counties and cities, which 
are regularly inspected by an authorized county or city inspector, 
and steam boilers operated or controlled by companies or corpora- 
tions which receive regular annual inspections by an inspector em- 
ployed by the said companies or corporations, shall be exempt from 
the regular annual inspections made by this Commission, on the 
following conditions : 

1. The boilers shall be installed and equipped with the 
fittings necessary to safety as prescribed by these Orders. 

2. The inspector or inspectors shall hold certificates of com- 
petency issued by the Industrial Accident Commission, or be 
dul}^ authorized as deputy inspectors. 

3. Reports of all annual inspections shall conform to the re- 
quirements of, and a copy of said reports shall be forwarded 
to this Commission within twenty-one (21) da^^s after the 
inspections are made, on the forms provided. 

Order 803. Certificate of competency. 

{a) As provided in chapter 202, Laws of 1917, upon the written 
request of an employer, certificates of competency shall be issued 
to persons who are employed as provided in section (c), and Avho 
pass an examination prescribed by the Industrial Accident Com- 
mission. Such examination shall determine the fitness and com- 
petency of candidates for said certificates.* 

(&) A certificate of competency may be revoked for cause at any 
time, but the holder of such certificate of competency shall be 
entitled, upon demand, to a hearing before the Industrial Accident 
Commission before the revocation of said certificate. 

(c) A certificate of competency shall be issued only to a person 
who is, or is to be, employed as inspector, only by any county, 
city, corporation or company, and shall be annulled upon the 
termination of his employment by the said city, county, corpora- 
tion or company, by which he was employed at the time of the 
issuance of the certificate. Such certificate may, however, be 

♦Candidates will be examined as to their knowledge of the construction, 
installation, operation, maintenance and repair of steam boilers, and of the rules 
governing Ijoilers in California. 



X TENTATIVE BOILER SAFETY ORDERS. 

renewed without re-examination within a period of one (1) year, 
upon proof that the applicant has been re-engaged as a boiler 
inspector. 

1. Any applicant who fails to pass the examination may 
apply for a re-examination at the end of ninety days. Pro- 
vided, however, that a person who has been refused a certificate 
of competency may appeal from such decision to the Indus- 
trial Accident Commission, who shall grant a re-hearing. The 
applicant shall have the privilege of having one representative 
of the county, city, corporation or company by whom he is 
or is to be employed, present during the hearing. 

(d) Upon the request of an employer, the Commission may per- 
mit an employee, after passing the prescribed examination, to act 
as a deputy inspector. Such deputy inspector may inspect and 
issue certificates of inspection for only such types of boilers as 
shall be specified in his permit. Such deputy inspectors' permits 
shall be subject to the same terms of revocation, annullment and 
renewal as specified in (h) and (c) of this Order. 

Order 804. Annual certificate of steam boiler inspection and permit 
to operate. 

(Hereafter referred to in these orders as the permit to operate.) 
(a) A permit to operate upon the forms supplied by the Indus- 
trial Accident Commission shall be issued by the inspector in the 
employ of the county, city, corporation, or company, stating the 
pressure allowed for one year after an inspection has been made. 
This permit to operate shall be kept conspicuously posted under 
glass on or near the boiler covered by it, and shall at all times be 
available when called for by a deputy of this Commission, or by an 
inspector holding a certificate of competency. 

Order 805. Stamps and numbers on boilers. 

(a) The owner or user of more than one steam boiler shall mark 
each boiler with his private number in some permanent manner, 
with figures not less than two and one-half (2^) inches in height. 

t (5) Every authorized inspector when making the first inspection 
of a boiler shall stamp on a designated place for that tj^pe of 
boiler, a number, except that boilers bearing a California standard 
number must not be stamped with a State serial number. This 
number must be either cut with steel dies not less than one-quarter 
(J) inch in height, or may be outlined by means of center punch 



flndicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 



TENTATIVE BOILER SAFETY ORDERS. xi 

dots, the figures to be not less than three-quarters (f) of an inch 
in height. This number shall be known as the State serial number 
and once assigned shall become the permanent means of identi- 
fication. 

t(c) State serial numbers shall be located in accordance with 
paragraph 363. after these orders become effective. 

■f{d) No state serial number or other boiler identifjdng number 
shall be covered by any insulating or other material. 

Order 806. New types of boilers. 

(a) Builders of new types of boilers subject to inspection shall 
forward to the Industrial Accident Commission blue prints and 
specifications of the type for approval. 

•Order 807. Safety regulations. 

(a) No boiler shall be operated, or the safety valve set, at a 
pressure in excess of the safe working pressure allowed by the 
annual permit to operate, which pressure is to be ascertained ])y 
means of these Orders. 

Order 808. 

(a) Boilers of twelve (12) horsepower or less, on which the pres- 
sure does not exceed fifteen (15) pounds per square inch, which 
are exempt from annual inspection, shall be fitted wath such 
appliances as to insure safety as herein prescribed. 

Order 809. 

(a) No new power boiler shall be installed in the State of Cali- 
fornia after January 1, 1917, which was not built to comply with 
the A. S. M. E. boiler code, except after a joint inspection by the 
Industrial Accident Commission and another inspector holding a 
certificate of competency. The lowest factor of safety on boilers 
of this kind shall be six (6), except that all new boilers carried in 
stock in this State on or before January 1, 1917, by dealers or 
private owners, may be installed after these Orders take effect, 
using a factor of safety as stipulated for existing installations; 
provided, that they shall be equipped with all the necessary 
appliances to comply with the herein Orders, as laid down for 
new installations; provided, further, that new boilers built prior 
to January 1, 1917, under the supervision and to the regulations 



flndicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 



Xll TENTATIVE BOILER SAFETY ORDERS. 

of the Interstate Railroad and/or the Interstate Commerce Com- 
mission, may also be installed and placed in operation under these 
same provisions. 

Order 810. 

(a) Steam boilers shall be equipped with such appliances as will 
insure safety of operation as herein ordered. 

Order 811. 

{a) No person shall tamper with any safety appliances pre- 
scribed by the herein Orders. 

Order 812. 

(a) In case a defect affecting the safety of a steam boiler is 
discovered, the owner or user of the boiler shall immediately notify 
the inspector issuing the permit to operate, but if said boiler be not 
subject to annual inspection, the owner or user shall in that case 
report the defect to the Industrial Accident Commission. The 
boiler shall not again be placed in service until the defect has 
been remedied. 

Order 813. 

j (a) All patches that were applied prior to January 1, 1917, on 
the boiler shell or drum which exceed twenty-four (24) inches in 
length measured in a line parallel to the longitudinal seam and 
between the center lines of the extreme rivet holes, shall be calcu- 
lated for safe working pressure from said patch seam, the efficiency 
of which shall be determined in accordance with paragraph 410 of 
the Appendix. 

(h) No double riveted horizontal patch seam shall be exposed to 
the products of combustion and all single riveted horizontal patch 
seams over three (3) pitches in length must be taken into account 
in calculating the strength of the boiler. 

After October 1, 1920, where a diagonal patch seam is applied to 
a boiler, it shall be designed in accordance with diagram No. 1. 



flndicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 






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XIV TENTATIVE BOILER SAFETY ORDERS. 

Order 814. 

{a) No cast iron hot water heating boiler shall carry a greater 
pressure, static or from supply main, than that named in the 
guarantee of the manufacturer. 

Order 815. 

{a) Where it is found impossible to definitely determine or 
reasonably estimate the age of a boiler, the factor of safety shall 
be not less than five and one-half (5J). 

(5) No pressure on a boiler of lap seam construction shall exceed 
one hundred and sixty-five (165) pounds per square inch. 

Order 816. 

(a) The use of plug cocks so constructed that there is no gland 
or yoke to hold the plug in place will not be allowed. If yokes or 
glands are of the open hole slot type at both ends, they shall have 
said slots effectively closed. 

t(5) The use of clip-gate valves for steam pressures in excess of 
twenty-five (25) pounds per square inch will not be allowed. 

Order 817. 

t {a) All hoods on vertical tubular boilers shall be provided with a 
door approximately rectangular in shape. For boilers up to and 
including 36 inches in diameter, lO^'xlO'' from 36'' to 48" in 
diameter a door 12" high by 16" wide over 48 inches in diameter, 
a door 15 inches high by 18 inches wide ; doors may vary from these 
dimensions, but the least dimension in any direction must not be 
smaller than that given above. Where cast iron hoods are 
provided, no door need be cut, but the hood must be removed for 
inspection purposes.* 

(6) Where boiler settings are so designed that gas can accumu- 
late to a dangerous extent, provision must be made for venting 
said gas pockets. 

(c) All dampers used in connection with oil burning furnaces 
under steam boilers shall be made with, or have suitable openings 
therein to vent the furnace from an accumulation of gas. Suitable 



♦Pending investigation by the Industrial Accident Commission, it is recom- 
mended that all externally fired fire tube boilers which are set up in new 
settings, be placed not less than the diameter of the boiler above the burner up 
to a maximum of 60 inches, except where boilers are added to an existing 
battery. It is further recommended that the space between the rear head of 
such boilers and rear wall of the combustion chamber be not less than half the 
diameter of the boiler with a minimum space of 24 inches and a maximum of 
40 inches. 



tindicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 



TENTATIVE BOILER SAFETY ORDERS. XV 

explosion doors or similar devices will be considered as carrying 
out the provisions of this Order. 

Order 818. 

{a) If there are valves in the connection between water column 
and boiler, at least one steam gauge shall be connected directly to 
steam space of boiler. (See paragraph 398.) 

t(6) The ends of the tubes in all fire tube boilers shall be sub- 
stantially beaded at the end nearest the fire, and at the end furthest 
from the fire they shall be either substantially beaded or flared not 
less than one-eighth inch over the diameter of the tube hole, in 
which case the tube shall extend through the head not less than 
one-quarter inch nor more than one-half inch. 

Order 819. 

(a) In determining the sizes of safety valves, the following 
table showing the ratio of heating surface to horsepower, shall be 
used : 



Type of boiler 



Water heating 
surface for 

1 horsepower. 
Square feet 



Cylindrical _ 

Flue — . 

Firebox tubular 
Return tubular . 

Vertical 

Water tube 



9 

10 
12 
15 
15 
10 



Order 820. A.S.M.E. Boiler Code. 

f (a) The Boiler Code, edition of 1918, with Index, of the Amer- 
ican Society of Mechanical Engineers, as copyrighted in 1918, is 
made a part of these Orders with certain changes and additions, 
all of which said changes and additions refer only to existing 
installations.* 

(&) All renewals, replacements or repairs on boilers that were 
built and installed in accordance with the A. S. M. E. Boiler Code 
must comply with the requirements of the 1918 edition of the said 
Code, as for new installations. See diagram No. 2. 



*It is recommended that all renewals, replacements or additions to any steam 
boilers of existing installations shall be in accordance with the provisions of 
the A. S. M. E. Boiler Code, edition of 1918, as for new installations. 



tindicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 



XVI 



TENTATIVE BOILER SAFETY ORDERS. 



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TENTATIVE BOILER SAFETY ORDERS. XVll 

« 

A.S.M.E. BOILER CODE 

PART II— EXISTING INSTALLATIONS 

Maximum Allowable Working Pressure 

378 (a) The maximum allowable working pressure on the shell 
of a boiler or drum shall be determined by the strength of the 
weakest course, computed from the thickness of the plate, the 
tensile strength of the plate, the efficiency of the longitudinal 
joint, the inside diameter of the course and the factor of safety 
allowed by these Rules. 

TSyctycE 

R\'F^ ~ ^^^i^u^ allowable working pressure, lb. per sq. in. 

where 

TS = ultimate tensile strength of shell plates, lb. per sq. in. 
t = thickness of shell plate, in weakest course, in. 
E = efficiency of longitudinal joint, method of determining 

which is given in Par. 181, of these Rules 
B = inside radius of the weakest course of the shell or drum, 
in. 
FS = factor of safety allowed by these Rules 

t(?>) The following rules shall apply in calculating the safe 
working pressure on staybolted vsurfaces. 

For all flat surfaces and for furnaces over 38'' diameter, out- 
side measurement : 

Divide the load in pounds allowed on a given staybolt b}^ the 
net area supported by the staybolt in square inches. 

Example : 

Pitch of staybolts=5'' x 5''. 

Diameter over threads of staybolts = J''. 

Net area at root of thread = .419 sq. in. 

Load allowed on f staybolt at 7500 lbs. per square inch equals 

.419 X 7500 = 3142 lbs. 
Net area supported by one staybolt = 5 X 5 == 25 s(]. in. 
Less area of staybolt = 25 — .419 = 24.581 sq. ins. 
3142 ^ 24.581 = 127 lbs. per sq. in. 

When the outside diameter of a furnace is 38'' or less, the stay- 
bolts shall be calculated as above and to the pressure thus found 

tindicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 

2—48403 



xvni 



TENTATIVE BOILER SAFETY ORDERS. 



may be added the pressure that the furnace would carry if there 
were no staybolts, using the following formula: 

C f' 
p= = 

where 

= a constant = 110. 

t = the thickness of the furnace in 32d of an inch. 

Z> = outside diameter of furnace. 

L = the length of the furnace in inches measured between the 

centers of rivets in the furnace tube sheet and those in 

the base ring. 

P = allowable working pressure in lbs. per sq. in. 

This formula may be used for unstayed plain cylindrical 
furnaces not over 38" in diameter, using a constant of 660, and 
using the same factor of safety as is used on. the shell of the boiler, 
except that in no case shall the factor of safety on the furnace be 
less than four and five-tenths (4.5). The formula then becomes 
p_ 660 r- 

fsxdxVl 

For unstayed plain cylindrical furnaces over 3 8" diameter, the rules for new 
installation will be used in calculating the safe working pressure. 

Table 9-A. AilowabJe loads on staybolts with "V" threads. 

(12 threads per inch and 3/16" diameter hole.) 



Outside diameter of 
staybolt in inches 



Net cross sectional area 

at bottom of thread, less 

.0276 sauare inches 



Allowable load at 7,500 

pounds stress per 

square inch 



4 -- 

16 - 

8 

IS./' 
16 - 

l''__ 

J-16 

J-s - 

1 _3_'' 
-'-16 

l-S.''' 

-^16 
13/'' 

-^s - 

1 _7_// 
-Ll6 

±2 - 



0.7500 
0.8125 
0.8750 
0.9375 
1.0000 
1.0625 
1.1250 
1.1875 
1.2500 
1.3125 
1.3750 
1.4375 
1.5000 



0.261 
0.324 
0.391 
0.467 
0.548 
0.635 
0.728 
0.827 
0.933 
1.045' 
1.163 
1.285 
1.416 



1,953 
2,425 
2,935 
3,498 
4,105 
4,765 
5,455 
6,205 
6,993 
7,833 
8,718 
9,640 
10,623 



Note. — Area 3/16 hole = .0276 square inches. For permissible loads on 
solid staybolts, see Tables 11 and 12. 



TENTATIVE BOILER SAFETY ORDERS. 



XIX 



(c) The maximum allowable stress per square inch net cross 
sectional area for various kinds of stays and staj^bolts is given in 
the following table : 



Material and type 



Si/e up to 

and incluJins 

14 diameter 

or cQuival-r^nt 

area 



Size over 

15 diame-er 

or equivalent 

area 



Weldless head to head or through stays- 
Iron 

Steel — _- 

Weldless diagonal or crowfoot stays- 
Iron 

Steel 

Welded portions of diagonal or crowfoot stays 
Iron or steel 

Mild steel or wrought iron staybolts 




8,000 
9,000 

7,500 
8,000 

6,500 
8,000 



Note.— 14 diameter equals 1.227 square inches. 

1379 Boilers of butt and double strap construction shall be 
operated with a factor of safety of at least four (4) by the for- 
mula, paragraph 378 (a), until January 1, 1922, after which date 
the factor of safety shall be at least four and five-tenths (4.5). In 
no case shall the maximum allowable working pressure on old boil- 
ers be increased, unless they are being operated at a lesser pres- 
sure than would be allowable for new bqilers, in which case the 
changed pressure shall not exceed that allowable for new boilers 
of the same construction. 

*380 (a) The lowest factor of safety used for boilers, the shells 

or drums of which are exposed to the direct products of combustion, 

and the longitudinal joints of which are of lap riveted construction, 

shall be as follows : 

4i for boilers not over five (5) years old. 

4i for boilers over five (5) and not over ten (10) years old. 

4f for boilers over ten (10) and not over fifteen (15) years old. 

5 for boilers over fifteen (15) and not over twenty (20) years old. 

For each five years thereafter the factor of safety shaU be 
increased by a further one-half (J) point, unless conditions are 
such as to warrant a continuance of a factor of safety of five (5). 

(&) The lowest factor of safety for boilers, the shells or drums of 
which are NOT exposed to the direct products of combustion, and 



flndicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 

♦Indicates changes, 1917, by the Industrial Accident Commission of the State 
of California. 



XX TENTATIVE BOILER SAFETY ORDERS. 

the longitudinal joints of which are of lap riveted construction, 

shall be as follows: 

4? for boilers not over ten (10) years old. 

4i for boilers over ten (10) and not over fifteen (15) years old. 
4^ for boilers over fifteen (15) and not over tAvent.y (20) years old. 
5 for boilers over twenty- (20) years old. 

For each five years thereafter, the factor of safety shall be 
increased by a further one-half (^) point, unless conditions are 
such as to warrant a continuance of a factor of safety of five (5). 

t381 (a) Second hand stationary boilers within this state on 
October 1, 1920, by which are meant boilers where both ownership 
and location are changed, shall if of lap seam construction, have a 
factor of safety of at least six (6). If of butt and double strap or 
lap welt construction, they shall have a factor of safety of at least 
five and one-half (5J), unless constructed in accordance with the 
rules contained in Part I, when the factor of safety shall be at 
least five (5). 

(h) No second hand lap seam boiler, not built to comply with 
the A. S. M. E. rules for new installation and not within this state 
prior to October 1, 1920, shall be operated at a pressure in excess of 
twenty-five (25) pounds per square inch. 

(c) Second hand boilers of butt and double strap construction, 
not built to comply with the A. S. M. E. Rules for new installa- 
tion, and not within this state prior to October 1, 1920, may be oper- 
ated after a thorough internal and external inspection. The safe 
working pressure shall be based upon the factor of safety of at 
least six (6).* 

1382 Cast-iron Headers and Mud Drums. All water tube boil- 
ers having cast iron headers, mud drums or junction boxes, shall, 
where conditions warrant, be permitted to carry pressures up to 
two hundred (200) pounds per square inch, provided that all such 
headers, mud drums and junction boxes shall be replaced with 
wroiight steel, steel eastings, malleable iron or wrought iron prior 
to January 1, 1922, or the pressure shall be so reduced as not to 
exceed one hundred sixty (160) pounds per square inch. 

t383 Steam Heating Boilers. The maximum allowable working 
pressure shall not exceed fifteen (15) pounds per square inch on a 

tindicates revision, 1920, by the Industrial Accident Commission of tlie State 
of California. 

*Note.— Order 381 does not apply to boilers already owned in this state wnich 
may be operated without its borders at the time these orders take effect or mav 
be taken outside of its borders and brought back. 



TENTATIVE BOILER SAFETY ORDERS. 



XXI 



boiler designed exclusively for low pressure steam heating, unless 
the manufacturers' specifications clearly show that the boiler was 
designed for a higher pressure. 

t384 The shell or drum of a boiler in which a typical "lap 
seam crack" is discovered along a longitudinal riveted joint for 
either butt seam or lap joints shall be permanently discontinued 
for use under steam, unless such defective course shall be entirely 
renewed and the longitudinal seams of all other courses thoroughly 
examined after removing all rivets and separating the plates. By 
"lap seam crack" is meant the typical crack frequently found in 
lap seams extending parallel to the longitudinal joint and located 
either between or adjacent to rivet holes. 

Strength of Materials. 

385 Tensile Strength. When the tensile strength of steel or 
wrought-iron shell plates is not known, it shall be taken as 55,000 lb. 
per sq. in. for steel and 45,000 lb. for wrought-iron. 

When the tensile strength of cast iron is not known, it shall be 
taken as 18,000 lbs. per sq. in. 

386 Strength of Rivets in Shear. In computing the ultimate 
strength of rivets in shear the following values in pounds per square 
inch of the cross-sectional area of the rivet shank shall be used : 

Iron rivets in single shear 38,000 

Iron rivets in double shear 76,000 

Steel rivets in single shear 44,000 

Steel rivets in double shear 88,000 

The cross-sectional area shall be that of the rivet shank after driving. 

387 Crushing Strength- of Mild Steel. The resistance to crush- 
ing of mild steel shall be taken at 95,000 lb. per sq. in. of cross- 
sectional area. 



Table 10. Sizes of Rivets Based on Plate Thickness. 



Thickness of plate 

Diam. of rivet after 
driving 


Iff 

4 

11'' 
16 


9 // 
y 2 

11" 
16 


5 '/ 

16 

4 


11'/ 

y 2 

4 


S 

1.3'/ 
16 


1 .•?// 

32 

13// 
16 


Thickness of plate 

Diam. of rivet after 
driving 


7 // 
T6 

15'' 
16 


Jl" 
11" 


1 5 // 
16 


9 //■ 
16 

^16 


5'/ 

8 

1 _1_" 
-Ll6 









flndicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 



XXll TENTATIVE BOILER SAFETY ORDERS. 

388 Rivets. When the diameter of the rivet holes in the longi- 
tudinal joints of a boiler is 7iot known, the diameter and cross- 
sectional area of rivets, after driving, may be ascertained from 
Table 10, for boilers built in an Eastern shop, or by cutting out 
one rivet in the body of the joint. 

3885 For boilers built on the Pacific Coast, the rivets are to be 
assumed as three-fourths (f ) of an inch before driving and thirteen- 
sixteenths (^f) of an inch after driving in five-sixteenths {j%) 
inch and eleven-thirty-seconds (|-J) inch plate. 

Safety Valves for Pov^er Boilers 

389 The safety valve capacity of each boiler shall be such that 
the safety valve or valves will discharge all the steam that can be 
generated by the boiler without allowing the pressure to rise more 
than 6 per cent above the maximum allowable working pressure, or 
more than 6 per cent above the highest pressure to which any valve 
is set. 

390 One or more safety valves on every boiler shall be set at or 
below the maximum allowable working pressure. The remaining 
valves may be set within a range of 3 per cent above the maximum 
allowable working pressure, but the range of setting of all of the 
valves on a boiler shall not exceed 10 per cent of the highest pres- 
sure to which any valve is set. 

391 Safety valve capacity may be checked in any one of three 
different ways, and if found sufficient, additional capacity need not 
be provided : 

a By making an accumulation test, that is, by shutting off 
all other steam-discharge outlets from the boiler and 
forcing the fires to the maximum. The safety valve 
equipment shall be sufficient to prevent an excess pres- 
sure beyond that specified in Par. 270. 

h By measuring the maximum amount of fuel that can be 
burned and computing the corresponding evaporative 
capacity upon the basis of the heating value of the fuel. 
See Appendix, Pars. 420 to 426. 

c By determining the maximum evaporative capacity by 
measuring the feedwater. The sum of the safety valve 
capacities shall be equal to or greater than the maximum 
evaporative capacity of the boiler. 



TENTATIVE BOILER SAFETY ORDERS. XXlll 

392 In case either of the methods outlined in sections & or c of 
Par. 391 is employed, the safety valve capacities shall be taken at 
the maximum values given in Table 15 for spring loaded pop safety 
valves, or 0.66 times the maximum values given in Table 15, for 
lever safety valves (see pages 118-120). 

393 When additional valve capacity is required, any valves 
added shall conform to the requirements in Part I of these rules. 

394 No valve of any description shall be placed between the 
safety valve and the boiler, nor on the discharge pipe between the 
safety valve and the atmosphere. When a discharge pipe is used, it 
shall be not less than the full size of the valve, and the discharge 
pipe shall be fitted with an open drain to prevent water lodging in 
the upper part of the safety valve or in the pipe. If a muffler is 
used on a safety valve it shall have sufficient outlet area to prevent 
back pressure from interfering with the proper operation and 
discharge capacity of the valve. The muffler plates or other devices 
shall be so constructed as to avoid any possibility of restriction of 
the steam passages due to deposit. When an elbow is placed on a 
safety valve discharge pipe, it shall be located close to the safety 
valve outlet or the pipe shall be securely anchored and supported. 
All safety valve discharges shall be so located or piped as to be 
carried clear from running boards or working platforms used in 
controlling the main stop valves of boilers or steam headers. 

Fittings and Appliances 

395 Water Glasses and Gage Cocks. Each steam boiler shall 
have at least one water glass, the lowest visible part of which shall 
be not less than 2 in. above the lowest permissible water level. 

396 Each boiler shall have three or more gage cocks, located 
within the range of the visible length of the water glass, when the 
maximum allowable working pressure exceeds 15 lb. per sq. in., 
except when such boiler has two water glasses with independent 
connections to the boiler, located on the same horizontal line and 
not less than 2 ft. apart. 

396a Exception should be made where the height of the segment 
above the tubes on the boiler does not exceed twelve (12) inches; 
in which case, at least two (2) gage cocfe located within the visible 
range of the water glass must be used. 

397 No outlet connections, except for damper regulator, feed- 
water regulator, drains or steam gages, shall be placed on the pipes 
connecting a water column to a power boiler. 



Xxiv TENTATIVE BOILER SAFETY ORDERS. 

398 steam Gages. Each steam boiler shall have a steam gage 
connected to the steam space or to the water column or to its steam 
connection. The steam gage shall be connected to a siphon or 
equivalent device of sufficient capacity to keep the gage tube filled 
with water and so arranged that the gage can not be shut off from 
the boiler except by a cock placed near the gage and provided with 
a tee or lever handle arranged to be parallel to the pipe in which it 
is located when the cock is open. Connections to gages shall be of 
brass, copper or bronze composition. 

899 Stop Valves.^ Each steam outlet from a power boiler 
(except safety valve connections) shall be fitted with a stop valve 
located as close as practicable to the boiler. 

400 When a stop valve is so located that water can accumulate, 
ample drains shall be provided. 

401 Bottom Blow-Off Pipes. Each boiler shall have a blow-off 
pipe fitted with a valve or cock, in direct connection with the lowest 
water space practicable. 

t402 When the maximum allowable working pressure exceeds 125 
lb. per sq. in., the blow-off pipe shall be extra heavy from boiler to 
valve or valves, and shall run full size without reducers or bushings. 

All fittings between the boiler and valve shall be steel or extra 
heavy fittings of bronze, brass, malleable iron or cast-iron. In 
case of replacement of pipe or fittings in the blow-off lines, as 
specified in this paragraph, they shall be installed in accordance 
with the rules for new installations (see Pars. -307-313). 

403 When the maximum allowable working pressure exceeds 125 
lb. per sq. in., each bottom blow-off pipe shall be fitted with an 
extra-heavy valve or cock. Preferably two valves, or a valve and 
a cock should be used on each blow-off, in which ease such valves, 
or valve and cock, shall be extra heavy. 

404 The blow-off pipe or boiler rest, or both, when exposed to 
direct action of products of combustion, shall be properly protected 
by a sleeve, asbestos rope, or other suitable material, or a protecting 
pier of brick built in ''V" shape, or other pier with corner pointing 
toward and against path of flame. 

405 An opening in the boiler setting for a blow-off pipe shall 
be arranged to provide for free expansion and contraction. 



*It is recommended that when two or more boilers are connected to a 
common steam main, two stop valves, with an ample free blow drain between 
them, be placed in the steam connection between each boiler and the steam 
main. Also that the discharge of this drain valve be visible to the operator 
while manipulating the valve and further that the stop valves consist preferably 
of one automatic non-return valve (set next the boiler) and a second valve of 
the outside screw and yoke type; or two valves of the outside screw and yoke 
type may be used. 



flndicates revision, 1920, by the Industrial Accident Commission of the State 
of California, 



TENTATIVE BOILER SAFETY ORDERS. XXV 

406 Feed Piping. The feed pipe of a steam boiler operated 
at more than 15 lb. per sq. in. maximum allowable working pressure, 
shall be provided with a check valve near the boiler and a valve or 
cock between the check valve and the boiler, and when two or more 
boilers are fed from a common source, there shall also be a globe 
valve on the branch to each boiler, between the check valve and the 
source of supply. When a globe valve is used on a feed pipe, the 
inlet shall be under the disk of the valve. 

t(&) A gravity feed may be considered as a mechanical means 
of feed where the pressure can be shown to be never less than 
ten (10) per cent in excess of the maximum allowable working 
pressure on the boiler. 

407 LampJirey Fronts. Each boiler fitted with a Lamphrey 
boiler furnace mouth protector, or similar appliance, having valves 
on the pipes connecting them to the boiler, shall have these valves 
locked or sealed open. Such valves, when used, shall be of the 
straightway type. 

408 Test Pressure, (a) When a hydrostatic test is applied the 
required test pressure shall be one and one-half times the maximum 
allowable working pressure. The pressure shall be under proper 
control so that in no case shall the required test pressure be exceeded 
by more than 2 per cent. 

(&) During a hydrostatic test of a boiler, the safety valve or 
valves shall be removed or each valve disk shall be held to its seat 
by means of a testing clamp and not by screwing down the com- 
pression screw upon the spring. 

f 409 Where repairs are necessary which in any way affect the 
working pressure or safety of a boiler, a state inspector, municipal 
inspector, or an inspector employed regularly by an insurance com- 
pany which is authorized to do a boiler-insurance business in the 
State of California, shall be called for consultation and advice as 
to the best method of making such ^repairs ; after such repairs are 
made they shall be subject to the approval of a state inspector, 
municipal inspector, or an inspector regularly employed by an 
insurance company which is authorized to do a boiler-insurance 
business in the State of California. 



flndicates revision, 1920, by the Industrial Accident Commission of the State 
of California. 



Note. — Particular attention is called to the recommendations for repairs 
when made by welding- and reinforcing by the electric oxyacetylene or other 
processes, shown in the Appendix on Pages — , — , and — of the A. S. M. E. 
Boiler Code, edition of 1918. 

3—48403 



RULES FOR THE 

CONSTRUCTION OF STATIONARY BOILERS AND 

FOR ALLOWABLE WORKING PRESSURES 



REPORT 

OF THE Committee to Formulate Standard 
Specifications for the 

construction of steam boilers 

AND Other Pressure Vessels and for 
Their Care in Service 



KNOWN AS 

THE BOILER CODE COMMITTEE 




THE AMERICAN SOCIETY OF MECHANICAL 

ENGINEERS 

Edition of 1918 

Copyright, 1918, by 
THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS 



To THE Council of The American Society op Mechanical Engineers: 

Gentlemen: Tour Committee respectfully submits the following revised 
report on Rules for the construction of, and allowable working pressures on 
stationary boilers, this report forming a part of the task that has been assigned 
to it. Stationary boilers as here considered are land boilers and include 
portable and traction boilers. The Eules do not apply to boilers which are 
subject to federal inspection and control, such as marine boilers, boilers of 
steam locomotives and other self-propelled railroad apparatus. 

The primary object of these Rules is to secure safe boilers. The interests 
of boiler users and manufacturers have been carefully considered and the 
requirements made such that they will not entail undue hardship by departing 
too widely from present practice. 

The Code applies only in part to certain special forms of boilers, such aa 
those of the forced-circulation or flash type. New matter has beeu added to 
state that the material for boilers of this class. shall conform to the require- 
ments of the Code, and that other requirements shall also be met except where 
they relate to special features of construction made necessary in boilers of 
this type, and to accessories that are manifestly not needed or used in con- 
nection with such boilers, such as water gages, water columns, and gage cocks. 

Your Committee has met monthly for the purpose of considering inquiries 
relative to the Boiler Code. The ordinary procedure in handling each Case is 
as follows: 

All inquiries must be in written form before they are accepted for consider- 
ation. Copies are sent by the Secretary of the Committee to all members of the 
Committee. The interpretation in the form of a reply is prepared by the Com- 
mittee, This interpretation is then submitted in typewritten form to each mem- 
ber of the Council of the Society, and to each member of the Committee. Where 
a single adverse criticism is received respecting any one of the interpretations, 
the inquiry is referred back to the Committee. Where there is no adverse 
criticism, the Council of the Society approves the interpretations which are 
then issued to the inquirer and simultaneously published in The Journal. In 
publishing the replies in The Journal, the names of firms and parties making 
the inquiries are withheld. Where there has been urgent need for haste, 
special action has been taken and the Executive Committee of the Council of 
the Society has acted for the Council. 

In accordance with your instructions, each State and Municipality that 
has adopted the Boiler Code has been invited to appoint a representative to 
act on a Conference Committee to the Boiler Code Committee, such Conference 
Committee to consist solely of representatives of the States and Municipalities 
that adopt the Code. The States and Municipalities have responded by appoint- 



ing representatives, who have attended the meetings and cooperated in the 
work of the Boiler Code Committee. The members of the Conference Committee 
are notified of and invited to attend all meetings of the Boiler Code Committee, 
and have rendered most useful assistance in preparing the interpretations as 
well as in cooperating with the Boiler Code Committee in revising the Code. 

In those states and municipalities which have adopted the Boiler Code, 
your Committee recommends that all requests for interpretations of the Boiler 
Code be referred to the state authorities having jurisdiction over such matters. 
In order to maintain uniformity of practice it is also suggested that the 
authorities having jurisdiction be requested to submit all inquiries where there 
is any question of doubt to the Boiler Code Committee. Where there is a 
question respecting the interpretation of the Code, or where constructions 
apparently are not covered by the Code, it will be most desirable to have 
the matter referred to the Boiler Code Committee. Unless this procedure is 
followed, the aim to obtain uniformity in the application of the Code will be 
defeated. The Boiler Code Committee desires to cooperate to the limit of 
its ability in assisting in the application of the Code, and will take pleasure 
in considering all matters where there is any question of doubt that may be 
brought before it by the various states and municipalities which adopt the Code. 

The specifications given in the Code are the same as, or similar to, those 
of the American Society for Testing Materials. The Specifications for Boiler 
Plate Steel published in the Code (Edition of 1914) were approved and 
recommended in their modified form, October 9, 1914, by The Association of 
American Steel Manufacturers, the American Boiler Manufacturers' Associa- 
tion, the National Tubular Boiler Manufacturers' Association, the National 
Association of Thresher Manufacturers and the representatives present of 
leading Water Tube Boiler Manufacturers, with whom the Boiler Code Com- 
mittee was in conference on September 16, 1914, and by whom further modi- 
fications were afterwards offered. 

The Specifications for Lapwelded and Seamless Boiler Tubes were approved 
by the Boiler Tube Manufacturers of America, September 25, 1914. Changes 
made in the specifications published in the original Code have been considered 
by sub-committees of the American Society for Testing Materials, of The 
Association of American Steel Manufacturers, and of the Boiler Code Committee 
in order that cooperation might be secured through these sub-committees 
making joint recommendations to their respective organizations. 

In the specifications for boiler plate steel, the range in tensile strength in 
pounds per square inch for firebox steel has been changed from 8000 to 10,000 
lb., the tensile strength now specified being from 55,000 to 65,000 lb. per sq. 
in., which is the same as for flange steel. Tour Committee believes that 
although there are certain features of the specifications for firebox steel which 
differentiate between the physical properties as compared with flange steel, 
there should be a further differentiation. This feature has been taken up 
with the Sub-Committees of the American Society for Testing Materials and 
of The Association of American Steel Manufacturers; but an agreement has 
not yet been reached. It was considered desirable not to delay the issuance of 
the revised Code until there could be an agreement, but to transmit the Code 
to you with the specifications in their present form, with the understanding 



that as soon as an agreement is reached a supplementary report will be sub- 
mitted to you for your consideration. 

Additional tests for firebox steel, which in the opinion of the Committee 
would entail the least hardship with a maximum benefit, would be homogeneity 
tests on the bend-test specimens, which are taken transversely from the 
middle of the top of the plate; the homogeneity tests to be made on the 
bend-test samples after the bend-tests are completed, thus requiring no 
additional specimens to be taken from the plate. Homogeneity tests are now 
specified for firebox steel on the tension-test specimens taken from the lower 
part of the plate ; and in the opinion of your Committee, it would be desirable 
to make additional homogeneity tests on the samples from the top of the 
plate where the metal is more apt to be segregated than near the bottom of 
the plate. 

The requirements for the homogeneity tests, at the top of the plate, may 
necessarily be different from those at the bottom of the plate, and until the 
requirements for the homogeneity tests at the top of the plate are determined 
by tests, the specifications cannot be changed to include the requirements. 

The rule for determining the strength of diagonal ligaments between tube 
holes in a drum, which is given in the preceding edition of the Code, has been 
found to be defective. Experiments have been made with a view of establish- 
ing a more exact rule. The experiments so far made indicate that certain 
theoretical curves which are published herein, in connection with Par. 193, 
are safe and accurate, and these curves axe therefore offered for determining 
the ef&ciency of such ligaments. The experiments projected by your Com- 
mittee are still proceeding, and it is possible that these may finally lead to 
minor modifications in the curves, in which case your Committee will present 
a new set of curves to take the place of those now offered. 

Your Committee recommends that a hearing be held by the Boiler Code 
Committee at least once in four years at which all interested parties may be 
heard, in order that such revisions may be made as are found to be desirable, 
as the state of the art advances. 

Tours truly, 

John A. Stevens, Chairman, Boiler Code Committee. 

"Wm. H. Boehm, Boiler Insurance. 

EoLLA C. Carpenter, Engineering Eesearch. 

Prank H. Clark, Eailroad Sub-Committee, A. S. M. E. 

PRANCIS W. Dean, Consulting Engineers. 

Thomas E. Durban, All types of boilers. (In military service.) 

E. E. Pish, American Boiler Manufacturers' Association. 

Elbert C. Fisher, Scotch marine and other types of boilers. 

Charles E. Gorton, Steel heating boilers. 

Arthur M. Greene, Jr., Engineering Education. 

EiCHARD Hammond, Scotch marine and olher types of boilers. 

A. L. Humphrey, Eailroad Sub-Committee, A. S. M. E. 

Charles L. Huston, Boiler-plate manufacturers. 

D. S. Jacobus, "Water-tube boilers- 

S. P. Jeter, Boiler Insurance. 

Wm, p. Kiesel, Jr., Eailroad Sub-Committee, A. S. M. E. 

P. E. Low, Technical Press. 



W. F. MacGregor, National Asscn. of Tractor and Thresher Manufacturers, 

Edward F. Miller, Engineering Eesearch. 

M. F. Moore, Steel heating boilers 

I. E. Moultrop, Boiler users. 

EiCHARD D. Reed, Cast-iron heating boilers. 

H. H. Vaughan, Railroad Sub-Committee, A. S. M. E. 

C, W. Obebt, Secretary to Committee. 

Conference Committee 

STATES 

California R. L. Hemingway. 

Minnesota V. E. Patnaude. 

New Jersey Joseph F. Scott. 

New York Thomas C. Eipper, 

Ohio C. O. Myers. 

Pennsylvania James Neil. 

Allegheny County Chas. H. Garlick. 

Wisconsin M. A. Edgar. 

cities 

Detroit, Mich J. C. McCabe. 

Erie, Pa James E. Speed. 

Kansas City, Mo M. B. Ryan. 

Philadelphia, Pa John M. Lukens. 

St. Louis, Mo H. F. Gauss. 



A.S.M.E. BOILER CODE 



RULES FOR THE 

CONSTRUCTION OF STATIONARY BOILERS 

AND FOR ALLOWABLE WORKING 

PRESSURES 



These Rules do not apply to toilers which are subject to federal 
inspection and control, including marine boilers, boilers of steam loco- 
motive and other self-propelled railroad apparatus. 



The Rules are divided into two parts: 

-r. A -r.rr, T i- j • i^ n x • fScctioii I, Powep Boileps. 

PAET I applies to new installations. ^ ^^ ,. tx tt i- t> •, 

I Section 11, Heating Boilers. 

PAET II applies to existing installations. 



CONTENTS 
Part I. New Installations pages 

Section 1. Power Boilers 5-88 

Section 2. Heating Boilers 89-96 

Part n. Existing Installations 97-102 

Appendix lt)3-128 



A.S.M.E. BOILER CODE 



PART I NEW INSTALLATIONS 

SECTION I 

POWER BOILERS 

iSelectioj^" of Mateeials 

1 Specifications are given in these Eules for the important ma- 
terials used in the construction of boilers, and where given, the ma- 
terials shall conform thereto. 

2 Steel plates for any part of a boiler when exposed to the fire 
or products of combustion, and under pressure, shall be of firebox 
quality as designated in the Specifications for Boiler Plate Steel. 

3 Steel plates for any part of a boiler, where firebox quality is 
not specified, when under pressure, shall be of firebox or flange quality 
as designated in the Specifications for Boiler Plate Steel. 

4 Braces when welded, shall be of wrought iron of the quality 
designated in the Specifications for Refined Wrought Iron Bars. 

5 Manhole and handhole covers and other parts subjected to pres- 
sure and braces and lugs, when made of steel plate, shall be of firebox 
or flange quality as designated in the Specifications for Boiler Plate 
Steel. 

6 iSteel bars for braces and for other boiler parts, except as other- 
wise specified herein, shall be of the quality designated in the Specifi- 
cations for Steel Bars; 

7 iStaybolts shall be of iron or steel of the quality designated in 
the Specifications for Staybolt Iron or in the .Specifications for Stay- 
bolt Steel. 



6 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

8 Rivets shall be of steel or iron of the quality designated in the 
Specifications for Boiler Rivet Steel or in the Specifications for 
Boiler Rivet Iron. 

9 Cross pipes connecting the steam and water drums of water- 
tube boilers, headers, cross boxes and all pressure parts of the 
boiler proper over 2-in. pipe size, or equivalent cross-sectional area, 
shall be of wrought steel, or cast steel of Class B grade, as designated 
in the Specifications for Steel Castings, when the maximum allow- 
able working pressure exceeds 160 lb. per sq. in. Malleable iron 
may be also used when the maximum allowable working pressure 
does not exceed 200 lb. per sq. in., provided the form and size of 
the internal cross-section perpendicular to the longest dimension 
of the box, is such that it will fall within a 7 in. by 7 in. rectangle. 

10 Mud drums of boilers used for other than heating purposes 
shall be of wrought steel, or cast steel of Class B grade, as designated 
in the Specifications for Steel Castings. 

11 Pressure parts of superheaters, separately fired or attached 
to stationary boilers, unless of the locomotive type, shall be of 
wrought steel, or cast steel of Class B grade, as designated in the 
Specifications for Steel Castings. 

12 Cast iron shall not be used for nozzles or flanges attached 
directly to the boiler for any pressure or temperature, nor for boiler 
and superheater mountings such as connecting pipes, fittings, valves 
and their bonnets, for steam temperatures of over 450 deg. fahr. 

13 Water-leg and door-frame rings of vertical fire-tube boilers 
and of locomotive and other type boilers, shall be of wrought iron 
or steel, or cast steel of Class A or Class B grade, as designated 
in the Specifications for Steel Castings. The OG or other flanged 
construction may be used as a substitute in any case. 

Ultimate Strength of Material used in Computing Joints 

14 Tensile Strength of Steel Plate. In determining the max- 
imum allowable working pressure, the tensile strength used in the 
computations for steel plates shall be that stamped on the plates 
as herein provided, which is the minimum of the stipulated range, 
or 55,000 lb. per sq. in. for all steel plates, except for special grades 
having a lower tensile strength. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 



15 Crushing Strength of Steel Plate. The resistance to crush- 
ing of steel plate shall be taken at 95,000 lb. per sq. in. of cross-sec- 
tional area. 

16 Strength of Rivets in Shear. In computing the ultimate 
strength of rivets in shear, the following values in pounds per square 
inch of the cross-sectional area of the rivet shank shall be used : 

Iron rivets in single shear 38,000 

Iron rivets in double shear 76,000 

Steel rivets in single shear 44,000 

Steel rivets in double shear 88,000 

The cross-sectional area used in the computations shall be that of 
the rivet shank after driving. 

Minimum Thicknesses of Plates and Tubes 

17 Thickness of Plates. The minimum thickness of any boiler 
plate under pressure shall be ^4 i^- 

18 The minimum thicknesses of shell plates, and dome plates 
after flanging, shall be as follows : 

When the Diameter of Shell is 
36 In. or Under Over 36 In. to 54 In. Over 54 In. to 72 In. Over 72 In. 
^ in. fg in. % in. % in. 

19 The minimum thickness of butt straps for double strap 
joints shall be as given in Table 1. Intermediate values shall be 
determined by interpolation. For plate thicknesses exceeding 1^ 
in., the thickness of the butt straps shall be not less than two-thirds 
of the thickness of the plate. 

table 1 minimum thicknesses of butt straps 



Thickness of 


Minimum Thickness 


Thickness of 


Minimum Thickness 


Shell Plates, 


of Butt Straps, 


Shell Plates, 


of Butt Straps, 


In. 


In. 


In. 


In. 


V4. 


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A 


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A 


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V4. 


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IV* 


% 


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8 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

20 The minimum thicknesses of tube sheets for horizontal re- 
turn tubular boilers, shall be as follows: 

When the Diameter op Tube Sheet is 

42 In. or Under Over 42 In. to 54 In. Over 54 In. to 72 In. Over 72 In, 
% in. ^ in. ^^ in. ^ in. 

21 Tubes for Water-Tube Boilers. The maximum allowable 
working pressures for tubes used in water-tube boilers shall be for 
the various diameters and gages measured by Birmingham wire 
gage, as given in Table 2. 

22 Tubes for Fire-Tube Boilers. The minimum thicknesses of 
tubes used in fire-tube boilers measured by Birmingham wire gage, 
for maximum allowable working pressures not exceeding 175 lb. 
per sq. in., shall be as follows : 

Diameters 1 in. or over, but less than 2^^ in No. 13 B.W.G. 

Diameter 2^^ in. or over, but less than 3}^ in No. 12 B.W.G. 

Diameter Si^ in. or over, but less than 4 in No. 11 B.W.G. 

Diameter 4 ' in. or over, but less than 5 in No. 10 B.W.G, 

Diameter 5 in No. 9 B.W.G. 

For each increase of one gage in thickness above that shown in 
the table, the maximum allowable working pressure will be in- 
creased by 200 lb. divided by the diameter of the tube in inches. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 



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MATERIAL SPECIFICATIONS 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 11 



SPECIFICATIONS FOR BOILER PLATE STEEL 



23 Grades, These specifications cover two grades of steel for 
boilers, namely : flange and firebox. 



I Manufacture 

24 Process. The steel shall be made by the open-hearth process. 

II Chemical Properties and Tests 

25 Chemical Composition. The steel shall conform to the fol- 
lowing requirements as to chemical composition : 

FLANGE FIREBOX 

Carbon Plates % in. thick and under. 0.12 — 0.25 per cent 

Plates over % in. thick. .. .0.12 — 0.30 per cent 

Manganese 0.30 — 0.60 per cent 0.30 — 0.50 per cent 

Phosphorus * ^^^^ • • • • ^^^ o^^^ 0.05 per cent Not over 0.04 per cent 

( Basic . . . Not over 0.04 per cent Not over 0.035 per cent 

Sulphur Not over 0.05 per cent Not over 0.04 per cent 

26 Ladle Analyses. An analysis shall be made by the manu- 
facturer from a test ingot taken during the pouring of each melt, a 
copy of which shall be given to the purchaser or his representative. 
This analysis shall conform to the requirements specified in Par. 25. 

27 Chech Analyses. Analyses may be made by the purchaser 
from a broken tension-test specimen representing each plate as 
rolled, which shall conform to the requirements specified in Par. 25. 

Ill Physical Properties and Tests 

28 Tension Tests, a The material shall conform to the follow- 
ing requirements as to tensile properties: 

flange firebox 

Tensile strength, lb. per sq. in 55,000 — 65,000 55,000 — 65,000 

Yield point, min., lb. per sq. in 0.5 tens str. 0.5 tens. str. 

1,500,000 1,500,000 



Elongation in 8-in., min., per cent (See Par'. 29) 



Tens. str. . Tens. str. 



12 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

h Should the above rule for minimum allowable elongation 
give a value of less than 24 per cent for firebox steel, the minimum 
allowable elongation shall be taken as 24 per cent, subject to the 
modification given in Par. 29. 

c If desired, steel of lower tensile strength than the above 
may be used in an entire boiler, or part thereof, the desired tensile 
limits to be specified, having a range of 10,000 lb. per sq. in. for 
both flange and firebox, the steel to conform in all respects to the 
other corresponding requirements herein specified, and to be stamped 
with the minimum tensile strength of the stipulated range. 

d The yield point shall be determined by the drop of the beam 
of the testing machine. 

29 Modifications in Elongation, a For material over ^346 i^- 
in thickness : From the figure representing the percentage of elon- 
gation required as determined in accordance with Par. 28 a, there 
shall be deducted an amount equal to four times the difference 
between the ordered thickness in inches and ^Yiq in., except that 
the minimum elongation required shall in no case be less than 20 
per cent. 

h For material % in. in thickness, the elongation shall be meas- 
ured on a gage length of 6 in. 

30 a Test Specimens. Tension-test specimens shall be taken 
longitudinally from the bottom of the finished rolled material, and 
bend-test specimens shall be taken transversely from the middle 
of the top of the finished rolled material. The longitudinal test 
specimen shall be taken in the direction of the longitudinal axis of 
the ingot, and the transverse-test specimen at right angles to that 
axis.^ 

h Bend Test. The bend-test specimen shall bend cold through 
180 deg. without cracking on the outside of the bent portion, as 
follows: For material 1 in. or under in thickness, around a pin 
the diameter of which is equal to the thickness of the specimen; 
and for material over 1 in. in thickness, around a pin the diameter 
of which is equal to twice the thickness of the specimen. 

81 Homogeneity Tests. For firebox steel, a sample taken from 
a broken tension-test specimen shall not show any single seam or 
cavity more than 14 iii- loi^g, in either of the three fractures obtained 
in the test for homogeneity, which shall be made as follows: 

* Exceptions are made for tension-test specimens for plate Avhioh is rolled longitudinally 
with reference to position when used in a boiler shell; see Par. 190. 



NEW INSTALLATIONS, PART I. SECTION I, POWER BOILERS 13 

The specimen shall be either nicked with a chisel or grooved on 
a machine, transversely, about 1/16 in. deep, in three places about 
2 in. apart. The first groove shall be made 2 in. from the square end; 
each succeeding groove shall be made on the opposite side from the 
preceding one. The specimen shall then be firmly held in a vise, with 
the first groove about ^ in. above the jaws, and the projecting end 
broken off by light blows of a hammer, the bending being away from 
the groove. The specimen shall be broken at the other two grooves in 
the same manner. The object of this test is to open and render visible 
to the eye any seams due to failure to weld or to interposed foreign 
matter, or any cavities due to gas bubbles in the ingot. One side of 
each fracture shall be examined and the length of the seams and 
cavities determined, a pocket lens being used if necessary. 

32 Specimens. Tension- and bend-test specimens shall be taken 
from the finished rolled material. They shall be of the full thick- 

..^ 

^ r" i^ ,.■<? i-< Pamtlel Section, ^ 

•< J - — H *5 \<- nof /ess than 9" "H 



<!. 






16 



Fig. 1 Standard Form of Test Specimen Eequired for all Tension Tests 

OF Plate Material 

ness of material as rolled, and shall be machined to the form and 
dimensions shown in Fig. 1 ; except that bend-test specimens may be 
machined with both edges parallel. 

33 Number of Tests, a One tension- and one bend-test shall 
be made from each plate as rolled. 

h If any test specimen shows defective machining or develops 
flaws, it may be discarded and another specimen substituted. 

c If the percentage of elongation of any tension-test specimen is 
less than that specified in Pars. 28 and 29, and any part of the frac- 
ture is outside the middle third of the gaged length, as indicated by 
the scribe scratches marked on the specimen before testing, a retest 
shall be allowed. 

IV Permissible Variation in Gage 

34 Permissible Variation. The thickness of each plate shall not 
vary under the gage specified more than 0.01 in. (The overweight 



14 EEPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

limits are considered a matter of contract between the steel manu- 
facturer and the boiler builder.) 

V Finish 

35 TPinish. The finished material shall be free from injurious 
defects and shall have a workmanlike finish. 

YI Maeking 

36 Marking, a Each shell plate shall be legibly stamped by 
the manufacturer with the melt or slab -number, name of manu- 
facturer, grade and the minimum tensile strength of the stipulated 
range as specified in Par. 28, in three places, two of which shall be 
located at diagonal corners about 12 in. from the edge and one about 
the center of the plate, or at a point selected and designated by the 
purchaser so that the stamp shall be plainly visible when the boiler is 
completed. 

h Each head shall be legibly stamped by the manufacturer in 
two places, about 12 in. from the edge, with the melt or slab number, 
name of manufacturer, grade, and the minimum tensile strength 
of the stipulated range as specified in Par. 28, in such manner that 
the stamp is plainly visible when the boiler is completed. 

c Each butt strap shall be legibly stamped by the manufacturer 
in two places on the center line about 12 in. from the ends with the 
melt or slab number, name of manufacturer, grade, and the minimum 
tensile strength of the stipulated range as specified in Par. ,28. 

d The melt or slab number shall be legibly stamped on each test 
specimen. 

YII Inspection" and Rejection 

37 Inspection. The inspector representing the purchaser shall 
have free entry, at all times while w^ork on the contract of the pur- 
chaser is being performed, to all parts of the manufacturer's works 
which concern the manufacture of the material ordered. The manu- 
facturer shall afiord the inspector, free of cost, all reasonable facilities 
to satisfy him that the material is being furnished in accordance with 
these specifications. All tests (except check analyses) and inspection 
shall be made at the place of manufacture prior to shipment, unless 
otherwise specified, and shall be so conducted as not to interfere un- 
necessarily with the operation of the works. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 15 

38 Rejection, a Unless otherwise specified, any rejection based 
on tests made in accordance with Par. ,27 shall be reported within five 
working days from the receipt of samples. 

h Material which shows injurious defects subsequent to its ac- 
ceptance at the manufacturer's works will be rejected, and the manu- 
facturer shall be notified. 

39 Rehearing. Samples tested in accordance with Par. ,37, which 
represent rejected material, shall be preserved for two weeks from the 
date of the test report. In case of dissatisfaction with the results of 
the tests, the manufacturer may make claim for a rehearing within 
that time. 



SPECIFICATIONS FOR BOILER RIVET STEEL 

A Requirements foe Rolled Bars 

I Manufacture 

40 Process. The steel shall be made by the open-hearth process. 

II Chemical Properties and Tests 

41 Chemical Composition. The steel shall conform to the fol- 
lowing requirements as to chemical composition : 

Manganese 0.30-0.50 per cent 

Phosphorus not over 0.04 per cent 

Sulphur not over 0.045 per cent 

42 Ladle Analyses. An analysis to determine the percentages 
of carbon, manganese, phosphorus and sulphur shall be made by the 
manufacturer from a test ingot taken during the pouring of each melt, 
a copy of which shall be given to the purchaser or his representative. 
This analysis shall conform to the requirements specified in Par. 41. 

43 Chech Analyses. Analyses may be made by the purchaser 
from finished bars, representing each melt, which shall conform to the 
requirements specified in Par. 41. 



16 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.D, 

III Physical Pkoperties and Tests 

44 Tension Tests, a The bars shall conform to the following 
requirements as to tensile properties : 

Tensile strength, lb. per sq. in 45,000-55,000 

Yield point, min., lb. per sq. in 0.5 tens. str. 

t7i ^. . o • • A. 1,500,000 

Elongation m 8 m., mm., per cent ' ' 

but need not exceed 30 per cent. Tens. str. 

h The yield point shall be determined by the drop of the beam of 
the testing machine. 

45 Bend Tests, a Cold-hend Tests — ^The test specimen shall 
bend cold through 180 deg. flat on itself without cracking on the out- 
side of the bent portion. 

h Quench-hend I'ests—T'he test specimen, when heated to a light 
cherry red as seen in the dark (not less than 1200 deg. fahr.), and 
quenched at once in water the temperature of which is between 80 deg. 
and 90 deg. fahr., shall bend through 180 deg. flat on itself without 
cracking on the outside of the bent portion. 

46 Test Specimens. Tension- and bend-test specimens shall be 
of the full-size section of the bars as rolled. 

47 Number of Tests, a Two tension, two cold-bend, and two 
quench-bend tests shall be made from each melt, each of which shall 
conform to the requirements specified. 

h If any test specimen develops flaws, it may be discarded and 
another specimen substituted. 

c If the percentage of elongation of any tension test specimen 
is less than that specified in Par. 44 and any part of the fracture is 
outside the middle third of the gaged length, as indicated by scribe 
scratches marked on the specimen before testing, a retest shall be 
allowed. 

48 Permissible Variations in Gage. The gage of each bar shall 
not vary more than 0.01 in. from that specified. 

Y Workmanship and Finish 

49 WorJcmanship. The finished bars shall be circular within 
0.01 in. 

50 Finish. The finished bars shall be free from injurious de- 
fects and shall have a. workmanlike finish. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 17 

yi Maeking 

51 MarMng. Eivet bars shall, when loaded for shipment, be 
properly separated and marked with the name or brand of the manu- 
facturer and the melt number for identification. The melt number 
shall be legibly marked on each test specimen. 

VII Inspection and Rejection 

62 Inspection. The inspector representing the purchaser shall 
have free entry, at all times while work on the contract of the pur- 
chaser is being performed, to all parts of the manufacturer's works 
which concern the manufacture of the bars ordered. The manu- 
facturer shall afford the inspector, free of cost, all reasonable facilities 
to satisfy him that the bars are being furnished in accordance with 
these specifications. All tests (except check analyses) and inspection 
shall be made at the place of manufacture prior to shipment, unless 
otherwise specified, and shall be so conducted as not to interfere "un- 
necessarily with the operation of the works. 

53 Rejection, a Unless otherwise specified, any rejection based 
on tests made in accordance with Par. 43 shall be reported within five 
working days from the receipt of samples. ^ 

h Bars which show injurious defects subsequent to their ac- 
ceptance at the manufacturer's works will be rejected, and the manu- 
facturer shall be notified. 

54 Rehearing. .Samples tested in accordance with Par. 43, which 
represent rejected bars, shall be preserved for two weeks from the 
date of the test report. In case of dissatisfaction with the results of 
the tests, the manufacturer may make claim for a rehearing within 
that time. 

B Requirements for Rivets 

I Physical Properties and Tests 

55 . Tension Tests, The rivets, when tested, shall conform to the 
requirements as to tensile properties speciffied in Par. 44, except that 
the elongation shall be measured on a gaged length not less than four 
times the diameter of the rivet. 

56 Bend Tests. The rivet shank shall bend cold through 180 
deg. flat on itself, as shown in Fig. 2, without cracking on the outside 
of the bent portion. 



18 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



57 Flattening Tests. The rivet head shall flatten, while hot, to 
a diameter .2% times the diameter of the shank, as shown in Fig. 3, 
without cracking at the edges. 

58 Number of Tests, a When specified, one tension, test shall 
be made from each size in each lot of rivets offered for inspection. 

h Three bend and three flattening tests shall be made from each 
size in each lot of rivets offered for inspection, each of which shall con- 
form to the requirements specified. 



II Workmanship an-d Finish 

59 Worlcmansliip. The rivets shall be true to form, concentric, 
and shall be made in a workmanlike manner. 

60 Finish, The finished rivets shall be free from injurious de- 
fects. 





Fig. 2 The Bend 
Test for Eivets 



Tig. 3 The Flat- 
tening Test fob 
Rivets 



III Inspection and Eejection 



61 Inspection. The inspector representing the purchaser shall 
have free entry, at all times while work on the contract of the pur- 
chaser is being performed, to all parts of the manufacturer's works 
which concern the manufacture of the rivets ordered. The manu- 
facturer shall afford the inspector, free of cost, all reasonable facilities 
to satisfy him that the rivets are being furnished in. accordance with 
these specifications. AH tests and inspection shall be made at the 
place of manufacture prior to shipment, unless otherwise specified, 
and shall be so conducted a$ not to interfere imnecessarily with the 
operation of the works. 

62 Rejection. Rivets which show injurious defects subsequent 
to their acceptance at the manufacturer's works will be rejected, and 
the manufacturer shall be notified. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 19 

SPECIFICATIONS FOR STAYBOLT STEEL 

REQUIREMENTS FOR ROLLED BARS 

63 Steel for staybolts shall conform to the requirements for 
Boiler Rivet Steel specified in Pars. 40 to 62, except that the tensile 
properties shall be as follows: 

Tensile strength, lb. per sq. in 50,000-60,000 

Yield point, min., lb. per sq. in 0.5 tens. str. 

Elongation in 8 in., min., per cent l,oOO,OQO 

Tens. str. 

Also with the exception that the permissible variations in gage shall 
be as follows: 

Permissible Variations in Gage. The bars shall be truly round 
within 0.01 in. and shall not vary more than 0.005 in. above, or more 
than 0.01 in. below the specified size. 



SPECIFICATIONS FOR STEEL BARS 

I Manufacture 

64 Process. The steel shall be made by the open-hearth process. 

II Chemical Properties and Tests 

65 Chemical Composition. The steel shall conform to the fol- 
lowing requirements as to chemical composition : 

( Acid not over 0.06 per cent 

Phosphorus I g^^.^ ^^^ ^^.^^ Q 04 p^^ ^^^^^ 

Sulphur not over 0.05 per cent 

QQ Ladle Analysis. An analysis to determine the percentages of 
carbon, manganese, phosphorus and sulphur shall be made by the 
manufacturer from a test ingot taken during the pouring of each 
melt, a copy of which shall be given to the purchaser or his representa- 
tive, This analysis shall conform to the requirements specified in 
Par. 65. 



20 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

Ill Physical Peopeeties and Tests 

67 Tension Tests, a The material shall conform to the follow- 
ing requirements as to tensile properties : 

Tensile strength, lb. per sq. in 55,000-65,000 

Yield point, min., per sq. in 0.5 tens. str. 

•oi i.- . o . • X* 1,500,000' 
Elongation in 8 in., mm., per cent* _! '. 

Elongation in 2 in., min., per cent 22 

*See Par. 68. 

h The yield point shall be determined by the drop of the beam of 
the testing machine. 

68 Modifications in Elongation, a For bars over % in. in 
thickness or diameter a deduction of 1 from the percentage of elonga- 
tion in 8 in. specified in Par. 67, shall be made for each increase of % 
in. in thickness or diameter above % in., to a minimum of 18 per cent. 

h For bars under 5/16 in. in thickness or diameter a deduction 
of 2.5 from the percentage of elongation in 8 in. specified in Par. 67, 
shall be made for each decrease of 1/16 in. in thickness or diameter 
below 5/16 in. 

69 Bend Tests, a The test specimen shall bend cold through 
180 deg. without cracking on the outside of the bent portion, as fol- 
lows : For material % in. or under in thickness or diameter flat on 
itself; for material over % in. to and including li/4 in. in thickness or 
diameter around a pin the diameter of which is equal to the thickness 
or diameter of the specimen ; and for material over 1% in. in thickness 
or diameter around a pin the diameter of which is equal to twice the 
thickness or diameter of the specimen. 

h The test specimen for bars over 1% in. in thickness or diameter 
when prepared as specified in Par. 70, shall bend cold through 180 
deg. around a 1-in. pin without cracking on the outside of the bent 
portion. 

70 Test Specimens, a Tension and bend test specimens except 
as specified in b, shall be of the full thickness of material as rolled. 
They may be machined to the form and dimensions shown in Fig. 1, 
or may have both edges parallel. 

h Tension test specimens for bars over l^^ in. in thickness or 
diameter may be of the form and dimensions shown in Fig. 4. Bend 



NEW INSTALLATIONS, PART I, SECTION I, POWER B0ILER3 21 

test specimens may be 1 by i/^ in. in section. The axis of the specimen 
shall be located at any point midway between the center and surface 
and shall be parallel to the axis of the bar. 

71 Number of Tests, a One tension and one bend test shall be 
made from each melt; except that if material from one melt differs 
% in. or more in thickness, one tension and one bend test shall be 
made from both the thickest and the thinnest material rolled. 

h If any test specimen shows defective machining or develops 
flaws, it may be discarded and another specimen substituted. 

c If the percentage of elongation of any tension test specimen is 
less than that specified in Par. 67, and any part of the fracture is 
more than % in. from the center of the gage length of a 2-in. specimen 
or is outside the middle third of the gage length of an 8-in. specimen, 
as indicated by scribe scratches marked on the specimen before testing, 
a retest shall be allowed. 

lY Permissible Yaeiations in Gage 

72 Permissible Variation, The thickness or cross-section of each 
piece of steel shall not vary under that specified more than 2.5 per 
cent. (N'ote: Overweight variation is a matter of contract between 
the steel manufacturer and boiler builder.) 

y Finish 

73 Finish. The finished material shall be free from injurious 
defects and shall have a workmanlike finish. 

,"VI MAKKINa 

74 Marlcing, Bars shall, when loaded for shipment, be properly 
separated and marked with the name or brand of the manufacturer 
and melt number for identification. 3?he melt number shall be legibly 
marked on each test specimen. 

yil Inspection and Bejeotion" 

75 Inspection, The inspector representing the purcliaser shall 
Ihave free entry, at all times while work on the contract of the pur- 
chaser is being performed, to all parts of the manufacturer's works 



22 rvEPORT OF BOILER CODE COMMITTEE, AM.SOC.M.B. 

which concern the manufacture of the material ordered. The manu- 
factnrer shall afford the inspector, free of cost, all reasonable facilities 
to satisfy him tliat the material is being furnished in accordance with 
these specifications. All tests and inspection shall be made at the place 
of manufacture prior to shipment, unless otherwise specified, and shall 
be so conducted as not to interfere unnecessarily with the operation of 
the works. 

76 Rejection, Materia! which shows injurious defects subsequent 
to its acceptance at the manufacturer's works will be rejected, and the 
manufacturer shall be notified. 



SPECIFICATIONS FOR STEEL CASTINGS 



77 Classes. These specifications cover two classes of castings, 
namely : 

Class A, ordinary castings for which no physical requirements 

are specified. 
Class B, castings for which physical requirements are specified. 

These are of three grades: hard, medium, and soft. 

78 Patterns, a Patterns shall be made so that sufficient finish 
is allowed to provide for all variations in shrinkage. 

& Patterns shall be painted three colors to represent metal, cores, 
and finished surfaces. It is recommended that core prints shall be 
painted black and finished surfaces red. 

79 Basis of Purcliase. The purchaser shall indicate his intention 
to substitute the test to destruction specified in Par. 87, for the tension 
and bend tests, and shall designate the patterns from which castings 
for this test shall be made. 

I Manufactuee 

80 Process. The steel may be made by the open-hearth, crucible, 
or any other process approved by the purchaser. 

81 Heat Treatment, a Class A castings need not be annealed 
unless so specified. 

h Class B castings shall be allowed to become cold. They shall 
then be uniformly reheated to the proper temperature to refine the 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 23 

grain (a group thns reheated being known as an "annealing charge"), 
and allowed to cool nnifornily and slowly. If, in the opinion of the 
purchaser or his representative, a casting is not properly annealed, he 
may at his option require the casting to be re-annealed. 

II Chemical Properties and Tests 

83 CJiemicdl Composition. The castings shall conform to the 
following requirements as to chemical composition; 

Class A Class B 

Carbon not over 0.30 per cent 

Phosphorus not over 0.06 per cent not over 0.05 per cent 

Sulphur not over 0,05 per cent 

83 Ladle Analyses. An analysis to determine the percentages of 
carbon, manganese, phosphorus and sulphur shall be made by the man- 
ufacturer from a test ingot taken during the pouring of each melt, a 
copy of which shall be given to the purchaser or his representative. 
This analysis shall conform to the requirements specified in Par. 82. 
Drillings for analysis shall be taken not less than % in. beneath the 
surface of the test in<rot. 



"O' 



84 Check Analyses, a Analyses of Class A castings may be 
made by the purchaser, in which case an excess of 20 per cent above the 
requirement as to phosphorus specified in Par. 8\2, shall be allowed. 
Drillings for analysis shall be taken not less than ^ in. beneath the 
surface. 

t Analyses of 'Class B castings may be made by the purchaser 
from a broken tension or bend test specimen, in which case an excess 
of 20 per cent above the requirements as to phosphorus and sulphur 
specified in Par. 82, shall be allowed. Drillings for analysis shall be 
taken not less than i/j^ in. beneath the surface. 



Ill Physical Properties and Tests 
(For Class B Castings only.) 

85 Tension Tests, a The castings shall conform to the follow- 
ing minimum requirements as to tensile properties: 



24 KEPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

Hard Medium Soft 

Tensile strength, lb. per sq. in - 80,000 70,000 60,000 

Yield point, lb. per sq. in 36,000 31,500 27,000 

Elongation in 2 in., per cent 15 18 22 

Reduction of area, per cent 20 25 30 

h The yield point shall be determined by the drop of the beam 
of the testing machine. 

86 Bend Tests, a The test specimen for soft castings shall bend 
cold through 1,30 deg., and for medium castings through 90 deg., 
around a 1-in. pin, without cracking on the outside of the bent portion. 

i) Hard castings shall not be subject to bend test requirements. 

B7 Alternative Tests io Destruction, In the case of small or un- 
important castings, a test to destruction on three castings from a lot 
may be substituted for the tension and bend tests. This test shall show 
the material to be ductile, free from injurious defects, and suitable 
for the purpose intended. A lot shall consist of all castings from one 
melt, in the same annealing charge. 

W> Test Specimens, (t Sufficient test bars, from which the test 
specimens required in Par. 89 may be selected, shall be attached to 
castings weighing 500 lb. or over, when the design of the castings will 
permit. If the castings weigh less than 500 lb., or are of such a design 
that test bars cannot be attached, two test bars shall be cast to represent 
each melt; or the quality of the castings shall be determined by tests 
to destruction as specified in Par. 87. All test bars shall be annealed 
with the castings they represent. 

h The manufacturer and purchaser shall agree whether test bars 
can be attached to castings, on the location of the bars on the castings, 
on the castings to which bars are to be attached, and on the method 
pf casting unattached bars. 

c Tension test specimens shall be of the form and dimensions 
shown in Fig. 4. Bend test specimens shall be machined to 1 by % 
in. in section with corners rounded to a radius not over ,1/16 in. 

89 Number of Tests, a One tension and one bend test shall be 
made from each annealing charge. If more than one melt is repre- 
eented in an annealing charge, one tension and one bend test shall be 
made from each melt. 

5 If any test specimen shows defective machining or develops 
flaws, it may be discarded; in which case the manufacturer and the 
purchaser or his representative shall agree upon the selection of an- 
other specimen in its stead. 



NEW INSTALLATIONS, PART I, SECTION I. POWER BOILERS 



25 



c If the percentage of elongation of any tension test specimen is 
less than that specified in Par. 85, and any part of the fracture is 
more than % in. from the center of the gaged length, as indicated by 
scribe scratches marked on the specimen before testing, a retest shall 
be allowed. 

IV WOEKMANSHIP AND FiNISH 

90 WorkmansMp. The castings shall substantially conform to 
the sizes and shapes of the patterns, and shall be made in a workman- 
like manner. 

91 Finish, a The castings shall be free from injurious defects. 
J) Minor defects which do not impair the strength of the castings 

may, with the approval of the purchaser or his representative, be 



>K-^>t<-"-^#"->t 




Fig. 4 Standard Form of Test Specimen Eequired for all Tension Tests 

OF Steel Casting Material 

welded by an approved process. The defects shall first be cleaned out 
to solid metal; and after welding, the castings shall be annealed, if 
specified by the purchaser or his representative. 

c The castings offered for inspection shall not be painted or 
covered with any substance that will hide defects, nor rusted to such 
an extent as to hide defects. 

Y IXSPECTION AND EeJECTION 



92 Inspection. The inspector representing the purchaser shall 
have free entry, at all times while work on the contract of the pur- 
chaser is being performed, to all parts of the manufacturer's works 
which concern the manufacture of the castings ordered. The manu- 
facturer shall afford the inspector, free of cost, all reasonable facilities 
to satisfy him that the castings are being furnished in accordance with 



26 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

these specifications. All tests (except check analyses) and inspection 
shall be made at the place of manufacture prior to shipment, unless 
otherwise specified, and shall be so conducted as not to interfere un- 
necessarily with the operation of the works. 

93 Rejection, a Unless otherwise specified, any rejection based 
on tests made in accordance with Par. 84, shall be reported within 
five w^orking days from the receipt of samples. 

h Castings which show injurious defects subsequent to their ac- 
ceptance at the manufacturer's works will be rejected, and the manu- 
facturer shall be notified. 

94 Rehearing. Samples tested in accordance with Par. 84, 
which represent rejected castings, shall be preserved for two weeks 
from the date of the test report. In case of dissatisfaction with the 
results of the tests, the manufacturer may make claim for a rehearing 
within that time. 



SPECIFICATIONS FOR GRAY IRON CASTINGS 



95 Process of Manufacture. Unless furnace iron is specified, all 
gray castings are understood to be made by the cupola process. 

96 Chemical Properties. The sulphur contents to be as follows: 

Light castings not over 0.08 per cent 

Medium eastings not over 0.10 per cent 

Heavy Castings not over 0.12 per cent 

97 Classification. In dividing castings into light, medium and 
heavy classes, the following standards have been adopted : 

98 Castings having any section less than % in. thick shall be 
known as liglit castings. 

99 Castings in which no section is less than 2 in. thick shall be 
known as heavy castings. 

100 Medium castings are those not included in the above classifi- 
cation. 



new installations, part i, section i, potter boilers 27 

Physical Properties and Tests 

101 Transverse Test. The minimiTm breaking strength of the 
"Arbitration Bar" under transverse load shall be not under: 

Light castings 2500 lbs. 

Medium castings 2900 lbs. 

Heavy castings 3300 lbs. 

In no case shall the deflection be under 0.10 in. 

103 Tensile Test. Where specified, this shall not run less than: 

Light eastings 18,000 lb. per sq. in. 

Medium castings 21,000 lb. per sq. in. 

Heavy castings 24,000 lb. per sq. in. 



Sfot. Thread 




Pig. 5 Standard Fcrm of Test Specimen Required for Tension Tests op 

Gray-Iron Casting Material 



103 Arhitratiofi Bar. The quality of the iron going into castings 
under specification shall be determined by means of the ''Arbitration 
Bar." This is a bar 1^ in. in diameter and 15 in. long. It shall be 
prepared as stated further on and tested transversely. The tensile 
test is not recommended, but in case it is called for, the bar as shown 
in Fig. 5, and turned up from any of the broken pieces of the trans- 
verse test shall be used. The expense of the tensile test shall fall on 
the purchaser. 

104: Number of Test Bars. Two sets of two bars shall be cast 
from each lieat, one set from the first and the other set from the last 
iron going into the castings. Where the heat exceeds twenty tons, an 
additional set of two bars shall be cast for each twenty tons or fraction 
thereof above this amount. In case of a change of mixture during 
the heat, one set of two bars shall also be cast for every mixture other 



28 



EEPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



than the regular one. Each set of two bars is to go into a single mold. 
The bars shall not be rumbled or otherwise treated, being simply 
brushed off before testing. 

105 Method of Testing. The transverse test shall be made on all 
the bars cast, with supports 12 in. apart, load applied at the middle, 



PATTERN 



|<-f>^ 



■i-H 



<-- /i 



A 

t 
I 



-> 



i 



r — ^^^ 



< 






^ 




> 



i 



10*' Pipe Cope ' .. 




k/jyy////. -: /.v. v///:wyyy;//;:y/y/yy7i^9:rT^ 



r 



Fig. 6 



Details of Pattern and Mold Eeqiitred for Arbitration Bars in 
Testing Gray-Iron Casting Material 



and the deflection at rupture noted. One bar of every two of each set 
made must fulfill the requirements to permit acceptance of the cast- 
ings represented. 

106 Mold for Test Bar. The mold for the bars is shown in Fig. 
6. The bottom of the bar is 1/16 in. smaller in diameter than the 
top, to allow for draft and for the strain of pouring. The pattern 
shall not be rapped before withdrawing. The fiask is to be rammed up 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 29 

with green molding sand, a little damper than usnal, well mixed and 
put through a No. 8 sieve, with a mixture of one to twelve bituminous 
facing. The mold shall be rammed evenly and fairly hard, thoroughly 
dried and not cast until it is cold. The test bar shall not be removed 
from the mold until cold enough to be handled. 

107 Speed of Testing. The rate of application of the load shall 
be from 20 to 40 seconds for a deflection of 0.10 in. 

108 Samples for Analysis, Borings from the broken pieces of 
the "Arbitration Bar" shall be used for the sulphur determinations. 
One determination for each mold made shall be required. In case of 
dispute, the standards of the American Foundrymen's Association 
shall be used for comparison. 

109 Finish. Castings shall be true to pattern, free from cracks, 
flaws and excessive shrinkage. In other respects they shall conform 
to whatever points may be specially agreed upon. 

110 Inspection. The inspector shall have reasonable facilities 
afforded him by the manufacturer to satisfy him that the finished 
material is furnished in accordance with these specifications. All 
tests and inspections shall, as far as possible, be made at the place of 
manufacture prior to shipment. 



SPECIFICATIONS FOR MALLEABLE CASTINGS 

HI Process of Manufacture. Malleable iron castings may be 
made by the open-hearth, air furnace, or cupola process. Cupola iron, 
however, is not recommended for heavy nor for important castings. 

112 Chemical Properties. Castings for which physical require- 
ments are specified shall not contain over 0.06 sulphur nor over 0.225 
phosphorus. 

Physical Properties and Tests 

11 ^ standard Test Bar. This bar sliall be 1 in. sq. and 14 in. 
long, without chills and with ends left perfectly free in the mold. 
Three shall be cast in one mold, heavy risers insuring sound bars. 
Where the full heat goes into castings which are subject to specifica- 



30 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.B. 

tion, one mold shall be poured two minntes after tapping into the first 
ladle, and another mold from the last iron of the heat. Molds shall be 
suitably stamped to insure identification of the bars, the bars being 
annealed with the eastings. Where only a partial heat is required for 
the work in hand, one mold should be east from the first ladle used 
and another after the required iron has been tapped. 

a Of the three test bars from the two molds required for eacK 
heat, one shall be tested for tensile strength and elongation, the other 
for transverse strength and deflection. The other remaining bar is 
reserved for either the transverse or tensile test, in case of the failure 
of the two other bars to come up to requirements. The halves of the 
bars broken transversely may also be used for the tensile test. 

h Failure to reach the required limit for the tensile strength 
with elongation, as also the transverse strength with deflection, on 
the part of at least one test, shall reject the castings from that heat- 

114 Tensile Test The tensile strength of a standard test bar 
for castings under specification shall not be less than 40,000 lb. 
per sq. in. The elongation measured in 2 in. shall not be less than 
2^2. per cent. 

115 Transverse Test The transverse strengtK of a standard test 
bar, on supports 12 in. apart, pressure being applied at the center, shall 
not be less than 3000 lb., deflection being at least ^2, i^* 

116 Test Lugs. Castings of special design or of special impor- 
tance may be provided with suitable test lugs at the option of the 
inspector. At least one of these lugs shall be left on the casting for 
his inspection upon his request therefor. 

117 Annealing. Malleable castings shall neitHer be '^^OYer" nor 
^'under'^ annealed. They must have received their full heat in the 
oven at least sixty hours after reaching that temperature. 

118 The ^^saggers'^ shall not be dumped until the contents shall 
at least be ^^black hot.'' 

119* Finish. Castings sHall be ivue to pattern, free from 
blemishes, scale or shrinkage cracks. A variation of 1/16 in. per foot 
shall be permissible. Founders shall not be held responsible for 
defects due to irregular cross sections and unevenly distributed metal. 

120 Inspection. The inspector representing the purchaser shall 
have all reasonable facilities given him by the founder to satisfy him 
that the finished material is furnished in accordance with these 
specifications. All tests and inspections shall be made prior to ship- 
ment. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 31 



SPECIFICATIONS FOR BOILER RIVET IRON 

A Requieemexts foe Rolled Baes 

I Manufacture 

121 Process. Tlie iron shall be made wholly from puddled iron 
or knobbled charcoal iron, and shall be free from any admixture of 
iron scrap or steel. 

122 Iron Scrap. This term applies only to foreign or bought 
scrap and does not include local mill products free from foreign or 
bought scrap. 

II Physical Peoperties and Tests 

123 Tension Tests, a Tiie iron shall conform to the following 
requirements as to tensile properties: 

Tensile strength, lb. per sq. in 48,000-52,000 

Yield point, min., lb. per sq. in 0.5 tens, str. 

Elongation in 8 in., min., per cent 28 

Keduction of area, min., per cent. 45 

h The yield point shall be determined by the drop of the beam 
of the testing machine. The speed of the cross-head of the machine 
shall not exceed 1% in. per minute. 

124 Bend Tests, a Cold-tend Tests — The test specimen shall 
bend cold through 180 deg. flat on itself without cracking on the out- 
side of the bent portion. 

b Hot-bend Tests — ^The test specimen, when heated to a bright 
cherry red, shall bend through 180 deg. flat on itself, without fracture 
on the outside of the bent portion. 

c Nick-bend Tests — The test specimen, when nicked 25 per cent 
around with a tool having a 60-deg. cutting edge, to a depth of not 
less than 8 nor more than 16 per cent of the diameter of the specimen, 
and broken, shall show a wholly fibrous fracture. 

d Bend tests may be made by pressure or by blows. 



S2 EEPORT OF BOILER CODE COMMITTEE, Alkl.SOC.M.B, 

125 Etch Tresis} The cross-section of the test specimen shall be 
ground or polished, and etched for a sufficient period to develop the 
structure. This test shall show the material to be free from steel. 

12G Test Specimens. All test specimens shall be of the full sec- 
tion of material as rolled. 

127 Number of Tests, a Bars of one size shall be sorted into 
lots of 100 each. Two bars shall be selected at random from each lot 
or fraction thereof, and tested as specified in Pars. 123 and 124; but 
only one of these bars shall be tested as specified in Par. 1,25. 

h If any test specimen from either of the bars originally selected 
to represent a lot of material, contains surface defects not visible before 
testing but visible after testing, or if a tension test specimen breaks 
outside the middle third of the gage length, one retest from a different 
bar will be allowed. 

Ill Permissible Variations in Gage 

128 Permissible Variations. The gage of each bar shall not vary 
more than 0.01 in. from that specified. 

lY Finish 

129 Finish. The bars shall be smoothly rolled and free from 
slivers, depressions, seams, crop ends and evidences of being burnt. 

V Marking 

130 MarJi-ing. The bars shall be stamped or marked as desig- 
nated by the purchaser. 

VI Inspection and Eejection 

131 Inspection, a The inspector representing the purchaser 
shall have free entry at all times, while work on the contract of the 
purchaser is being performed, to all parts of the manufacturer's works 
which concern the manufacture of the material ordered. The manu- 
facturer shall afford the inspector, free of cost, all reasonable facilities 
to satisfy him that the material is being furnished in accordance with 



^ a solution of two parts water, one part concentrated hydrochloric acid, and one part 
concentrated sulphuric acid is recommended for the etch test. 



NEW INSTALLATIONS, PART I, SECTION I. POWER BOILERS 33 

these specifications. Tests and inspection at the place of manufacture 
shall be made prior to shipment. 

h The purchaser may make the tests to govern the acceptance or 
rejection of material in his own laboratory or elsewhere. iSuch tests, 
however, shall be made at the expense of the purchaser. 

13S Rejection. If either of the test bars selected to represent a 
lot does not conform to the requirements specified in Pars. 13(3, 134 
and 125, the lot will be rejected. 

B Requirements foe Eivets 
Ii Physical Properties and Tests 

133 Numher of Tests. When specified, three rivets of each di- 
ameter shall be taken at random from each lot offered for inspection, 
and if they fail to stand the following tests the lot will be rejected. 

134 Bend Tests, a The rivet shank shall bend cold through 
180 deg. flat on itself, as shown in Fig. 2, without cracking on the out- 
side of the bent portion. 

h Th'e heads must stand bending back, showing that they are 
firmly joined. 

c When nicked and broken gradually the fracture must show a 
clean, long and fibrous iron. 

II Workmanship and Finish 

135 Workmanship. The rivets shall be true to form, concentric, 
and shall be made in a workmanlike manner. 

13 G Finish. The finished rivets shall be free from injurious de- 
fects. 

Ill Inspection and Eejection* 

137 Inspection. The inspector representing the purchaser shall 
have free entry at all times, while work on the contract of the pur- 
chaser is being performed, to all parts of the manufacturer's works 
which concern the manufacture of the rivets ordered. The manu- 
facturer shall afford the inspector, free of cost, all reasonable facilities 
to satisfy him that the rivets are being furnished in accordance with 
these specifications. All tests and inspection shall be made at the 



34 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

place of manufacture prior to sliipment, unless otherwise specified, and 
shall be so conducted as not to interfere unnecessarily with the opera- 
tion of the works. 

13i8 Rejection. Rivets which show injurious defects subsequent 
to their acceptance at the manufacturer's works will be rejected, and 
the manufacturer shall be notified. 



SPECIFICATIONS FOR STAYBOLT IRON 



I Man'ufacture 

139 Process. The iron shall be rolled from a bloom or boxpile, 
made wholly from puddled iron or knobbled charcoal iron. The 
puddle mixture and the component parts of the bloom or boxpile shall 
be free from any admixture of iron scrap or steel. 

140 Definition of Tei^ms. a Bloom — A bloom is a solid mass of 
iron that has been hammered into a convenient size for rolling. 

t Boxpile — lA boxpile is a pile, the sides, top and bottom of which 
are formed by four flat bars and the interior of which consists of a 
number of small bars the full length of the pile. 

c Iron Scrap — 'This term applies only to foreign or purchased 
scrap and does not include local mill products free from foreign or 
purchased scrap. 

II Physical Properties and Tests 

141 Tension Tests, a The iron shall conform to the following 
requirements as to tensile properties: 

Tensile strength, lb. per sq. in 49,000-53,000 

Yield point, min., lb. per sq. in 0.5 tens. str. 

Elongation in 8 in., min., per cent 30 

Eeduction of area, min., per cent 48 

& The yield point shall be determined by the drop of the beam 
of the testing machine. The speed of the cross-head of the machine 
shall not exceed 1% in. per minute. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 35 

142 Bend Tests, a Cold-hend Tests — The test specimen shall 
bend cold through 180 deg. flat on itself in both directions without 
fracture on the outside of the bent portion. 

b Quench-hend Tests — 'The test specimen, when heated to a yel- 
low heat and quenched at once in water the temperature of which is 
between 80 deg. and 90 deg. fahr., shall bend through 180 deg. flat on 
itself without fracture on the outside of the bent portion. 

c Niclc-hend Tests — The test specimen, when nicked 25 per cent 
around with a tool having a 60-deg. cutting edge, to a depth of not 
less than 8 nor more than 16 per cent of the diameter of the specimen, 
and broken, shall show a clean fiber entirely free from crystallization. 

d Bend tests may be made by pressure or by blows. 

143 Etch Tests^ The cross-section of the test specimen shall be 
ground or polished, and etched for a sufficient period to develop the 
structure. This test shall show the material to have been rolled from 
a bloom or a boxpile, and to be free from steel. 

144 Test Specimens. All test specimens shall be of the full sec- 
tion of material as rolled. 

145 Number of Tests, a Bars of one size shall be sorted into 
lots of 100 each. Two bars shall be selected at random from each lot 
or fraction thereof, and tested as specified in Pars. 141 and 142; but 
only one of these bars shall be tested as specified in Par. 143. 

h If any test specimen from either of the bars originally selected 
to represent a lot of material, contains surface defects not visible be- 
fore testing but visible after testing, or if a tension test specimen 
breaks outside the middle third of the gage length, one retest from a 
different bar will be allowed. 

c When retests as specified in h are not permitted, a reduction 
of 2 per cent in elongation and 3 per cent in reduction of area from 
that specified in Par. 141, shall be allowed. 



Ill Permissible Variations in Gage 

146 Permissible Variations. The bars shall be truly round 
within 0.01 in., and shall not vary more than 0.005 in. above or more 
than 0.01 in. below the specified size. 



* A solution of two parts water, one part concentrated hydrochloric acid, and one 
paft concentrated sulphuric acid is recommended for the etch test. 



36 KEPORT OF BOILER CODE COMMITTEE, AM.SOO^.5 

IV Finish 

147 Finish. The bars shall be smoothly rolled and free from 
slivers, depressions, seams, crop ends and evidences of being burnt. 

Y Haeking 

148 Marl'ing. The bars shall be stamped or marked as desig- 
nated by the purchaser. 

YI Inspection* and Ebjection 

149 Inspection, a The inspector representing the purchaser 
shall have free entry, at all times while work on the contract of the 
purchaser is being performed, to all parts of the manufacturer's works 
which concern the manufacture of the material ordered. The manu- 
facturer shall afford the inspector, free of cost, all reasonable facilities 
to satisfy him that the material is being furnished in accordance with 
these specifications. Tests and inspection at the place of manufacture 
shall be made prior to shipment. 

h The purchaser may make the tests to govern the acceptance or 
rejection of material in his own laboratory or elsewhere. Such tests, 
however, shall be made at the expense of the purchaser. 

150 Rejection, a If either of the test bars selected to represent 
a lot does not conform to the requirements specified in Pars. 141, 142 
and 143, the lot will be rejected. 

h Bars which will not take a clean, sharp thread with dies in fair 
condition, or which develop defects in forging or machining, will be 
rejected, and the manufacturer shall be notified. 



NEW INSTALLATIONS, PART I, SECTION I, TOWER BOILERS 37 



SPECIFICATIONS FOR REFINED WROUGHT-IRO N" 

BARS 



I Manufacture 

151 Process. Eefined wrought-iron bars shall be made wholly 
from puddled iron, and may consist either of new muck-bar iron or a 
mixture of muck-bar iron and scrap, but shall be free from any ad- 
mixture of steel. 

II Physical Properties and Tests 

152 Tension Tests, a The iron shall conform to the following 
minimun/Tequirements as to tensile properties. 

Tensile strength, lb. per sq. in 48,000 

(See Pars. 153 and 154.) 

Yield point, lb. per sq. in 25,000 

Elongation in 8 in., per cent 22 

(See Par. 155.) 

& The yield point shall be determined by the drop of the beam 
of the testing machine. The speed of the cross-head of the machine 
shall not exceed l^/^ in. per minute. 

153 Permissible Variations. Twenty per cent of the test speci- 
mens representing one size may show tensile strengths 1000 lb. per 
8q. in. under, or 5000 lb. per sq. in. over that specified in Par. 152; 
but no specimen shall show a tensile strength under 45,000 lb. per 
sq. in. 

154 Modifications in Tensile Strength. For flat bars which ha\'e 
to be reduced in width, a deduction of 1000 lb. per sq. in. from the 
tensile strength specified in Pars. 152 and 153, shall be made. 

155 Permissible Variutions in Elongation. Twenty per cent of 
the test specimens representing one size may show the following per- 
centages of elongation in 8 in. : 

EOUND BARS 

% in. or over, tested as rolled 20 per cent 

Under % in., tested as rolled 16 per cent 

Eeduced by machining 18 per cent 



38 KEPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

FLAT BAES 

% in. or over, tested as rolled 18 per cei?t 

Under % in., tested as rolled 16 per cent 

Reduced by machining 16 per cent 

15G Bend Tests, a CoM-hend Tests — Cold bend tests will be 
made only on bars having a nominal area of 4 sq. in. or under, in 
which case the test specimen shall bend cold through 180 deg. without 
fracture on the outside of the bent portion, around a pin the diameter 
of which is equal to twice the diameter or thickness of the specimen. 

h Hot-hend Tests — 'The test specimen, when heated to a tempera- 
ture between 1700 deg. and 1800 deg. fahr., shall bend through 180 
deg. without fracture on the outside of the bent portion, as follows : 
for round bars under 2 sq. in. in section, flat on itself ; for round bars 
2 sq. in. or over in section and for all flat bars, around a pin the 
diameter of which is equal to the diameter or thickness of the specimen. 

c NicJc-hend Tests — The test specimen, when nicked 25 per cent 
around for round bars, and along one side for flat bars, with a tool 
having a 60-deg. cutting edge, to a depth of not less than 8 nor more 
than 16 per cent of the diameter or thickness of the specimen, and 
broken, shall not show more than ,10 per cent of the fracture surface 
to be crystalline. 

d Bend tests may be made by pressure or by blows. 

157 Etch Tests.^ The cross-section of the test specimen shall be 
ground or polished, and etched for a sufficient period to develop the 
structure. This test shall show the material to be free from steel. 

158 Test Specimens, a Tension and bend test specimens shall 
be of the full section of material as rolled, if possible; otherwise the 
specimens shall be machined from the material as rolled. The axis 
of the specimen shall be located at any point one-half the distance 
from the center to the surface of round bars, or from the center to 
the edge of flat bars, and shall be parallel to the axis of the bar. 

h Etch test specimens shall be of the full section of material as 
rolled. 

159 ITumber of Tests, a AH bars of one size shall be piled 
separately. One bar from each 100 or fraction thereof will be selected 
at random and tested as specified. 

h If any test specimen from the bar originally selected to repre- 
sent a lot of material contains surface defects not visible before test- 



^A solution of two parts water, one part concentrated hydrochloric acid, and one part con- 
centrated sulphuric acid ia recommended for the etch test. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 89 

ing but visible after testing, or if a tension test specimen breaks outside 
the middle third of the gage length, one retest from a different bar 
will be allowed. 

Ill Permissible Variations in Gage 

160 Permissible Variations, a Round bars shall conform to 
the standard limit gages adopted by the Master Car Builders' Asso- 
ciation given in Table 3. 

TABLE 3 PERMISSIBLE VARIATIONS IN GAGE FOR ROUND WROUGHT-IRON BARS 



Nominal 

Diameter, 

Inches 


Maximum 

Diameter, 

Inches 


Minimum 

Diameter, 

Inches 


Total 

Variation, 

Inches 


li 


0.2550 
0.3180 
0.3810 
0.4440 
5070 
0.5700 
0.6330 
0.7585 
0.8840 
1.0095 
1 . 1350 
1.2605 


0.2450 
0.3070 
0.3690 
0.4310 
0.4930 
0.5550 
0.6170 
0.7415 
0.8660 
0.9905 
1.1150 
1.2395 


0.010 


t ::::::::::::::::::: 


0.011 


u 


0.012 


A.. ... • ... 


0.013 


?i : :: .: 


0.014 


A 


0.015 


H...y-. ............ ........... ... 


0.016 


M .... 


0.017 


j| ... 


0.018 


1 , 


0.019 


m 


0.020 


iy£ 


0.021 







1) The widths or thicknesses of flat bars shall not vary more 
than 2 per cent from that specified. 

IV Finish 

161 Finish. The bars shall be smoothly rolled and free from 
slivers, depressions, seams, crop ends and evidences of being burnt. 

V Inspection and Rejection 

16^ Inspection, a The inspector representing the purchaser 
shall have free entry, at all times while work on the contract of the 
purchaser is being performed, to all parts of the manufacturer's 
works which concern the manufacture of the material ordered. The 
manufacturer shall afford the inspector, free of cost, all reasonable 
facilities to satisfy him tliat the material is being furnished in ac- 
cordance with these specifications. 'Tests and inspection at the place 
of manufacture shall be made prior to shipment. 

h The purchaser may make the tests to govern the acceptance 
or rejection of material in his own laboratory or elsewhere. Such 
tests, however, shall be made at the expense of the purchaser. 

163 Rejection. All bars of one size will be rejected if the test 
specimens representing that size do not conform to the requirements 
specified. 



40 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

SPECIFICATIONS FOR LAPWELDED AND SEAMLESS 

BOILER TUBES 

I Manufacture 

164 Process, a Lapwelded tubes shall be made of open-hearth 
steel or knobbled, hammered charcoal iron. 

h Seamless tubes shall be made of open-hearth steel. 

II Chemical Properties and Tests 

165 'Chemical Composition, a The steel shall conform to the 
following requirements as to chemical composition: 

Carbon 0.08-018 per cent 

Manganese . . •. 0.30-0.60 per cent 

Phosphorus not over 0.04 per cent 

Sulphur not over 0.045 per cent 

T) Chemical analyses will not be required for charcoal iron tubes. 

166 Check Analyses, a Analyses of two tubes in each lot of 
250 (or on total order if less than 250) may be made by the purchaser 
which shall conform to the requirements specified in Par. 165. Drill- 
ings for analyses shall be taken from several points around each tube. 

h If the analysis of only one tube does not conform to the re- 
quirements specified, analyses of two additional tubes from the same 
lot shall be made, each of which shall conform to the requirements 
specified. 

III Physical Properties and Tests 

167 Flange Test, a For tubes not more than 6 in. diameter, 
having a thickness less than 10 per cent of the outside diameter, 
provided the thickness does not exceed No. 6 B.W.G., a test speci- 
men not less than 4 in. in length shall have a flange turned over 
at right angles to the body of the tube without cracking or showing 
any flaw. This flange as measured from the outside of the tube 
shall have a width of from % in. to % in., the width between these 
limits to be not less than 10 per cent of the outside diameter of 
the tube. For other tubes the flange test is not required. 

I In making the flange test, the flaring tool and die block as 
shown in Fig. 7, may be used. 

168 Flattening Tests. A test specimen 3 in. in length shall 
stand flattening between two parallel plates until the distance 
between the plates is not over five times the wall thickness, without 
showing cracks or flaws. In the case of lapwelded tubes, the test 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 



41 



shall be made with the weld at the point of maximum bend. 

169 Hydrostatic Tests. Tubes under 5 in. in diameter shall 
stand an internal hydrostatic pressure of 1000 lb. per sq. in. and 
tubes 5 in. in diameter or over, an internal hydrostatic pressure of 
800 lb. per sq. in., provided the fibre stress corresponding to these 
pressures does not exceed 16,000 lb. per sq. in. 

Should the fibre stress corresponding to these pressures exceed 
16,000 lb. per sq. in., the test pressure shall be determined by the 
following formula: 

32000 t 



P = 



D 




FLARING TOOL 
A = O.S. D'lam. of Tube less § 
B - >* " •» •» " § " 
Q ~ » » " '/ p/us ^' 



Position offer using f /erring Tool 
^v Position after using 
'^^^srmn/iu flatter 




K--A -^'"L/ners 
DIE BLOCK 
O.S. Diam. of Tube * j£" 



Fig. 7 Details of Flaring Tool and Die Block Eequired for Making 

Flange Tests of Boiler Tubes 



where i is the wall thickness in inches ; D is the inside diameter in 
inches. Lapwelded tubes shall be struck near both ends, while under 
the test pressure, with a 2 lb. steel hand hammer, or the equivalent. 

170 Test Specimens, a All test specimens shall be taken from 
tubes before being cut to finished lengths and shall be smooth on the 
ends and free from burrs, h All tests shall be made cold. 

171 Number of Tests. All tubes shall be subjected to the 
hydrostatic test. One of each of the physical tests specified shall 
be made k-om each of two tubes in each lot of 250 or less. 

172 Retests. If the result of the physical tests of only one tube 
from any lot do not conform to the requirements specified in Pars. 
167 and 168, retests of two additional tubes from the same lot shall 
be made, each of which shall conform to the requirements specified. 



42 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

ETCH TESTS FOR CHARCOAL IRON 

173 Etch Tests} A cross section of tube may be turned or 
ground to a perfectly true surface polished free from dirt or cracks, 
and etched until the soft parts are sufficiently dissolved for the iron 
tube to show a decided ridged surface with the weld very distinct, 
while a steel tube would show a homogeneous surface. 

. IV "Workmanship and Finish 

174 Workma'iiship. Finished tubes 3% in. or under in outside 
diameter shall be circular within 0.02 in. and the mean outside 
diameter shall not vary more than 0.015 in. from the size ordered. 
For tubes over 3% in. in outside diameter, these variations shall 
not exceed 0.5 per cent of the outside diameter. All tubes shall be 
carefully gaged with a B.W.G. gage and shall not be less than the 
gage specified. Tubes on which the standard slot gage specified will 
go on tightly at the thinnest point, will be accepted. The length 
shall not be less, but may be 0.125 in. more than that ordered. 

175 Finish. The finished tubes shall be free from injurious 
defects and shall have a workmanlike finish and shall be practically 
free from kinks, bends and buckles. 

V Marking 

176 Marking. The name or brand of the manufacturer, the 
material from which it is made, and the pressure in pounds per 
square inch at which it was tested, shall be legibly stenciled on each 
tube. 

VI Inspection and Rejection 

177 Inspection. All tests and inspection shall be made at the 
place of manufacture. The manufacturer of boiler tubes shall 
furnish the purchaser of each lot of tubes a statement of the kind 
of material of which the tubes are made, and that the tubes have 
been tested and have met all the requirements of these rules. This 
statement shall be furnished to the manufacturer using the tubes. 

178 Rejection. Tubes when inserted in the boiler shall stand 
expanding and beading without showing cracks or flaws, or opening 
at the weld. Tubes which fail in this manner will be rejected and 
the manufacturer shall be notified. 



^A solution of two parts of water, one part concentrated hydrochloric acid, and one part 
concentrated sulphuric acid is recommended for the etch test. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 43 



CONSTRUCTION 



CONSTKUCTION AND MAXIMUM ALLOWABLE WORKING PRESSURES 

FOR Power Boilers 

179 Maximum Allowable Working Pressure. The maximum al- 
lowable working pressure is that at which a boiler may be operated as 
determined by employing the factors of safety, stresses, and dimensions 
designated in these Eules. 

No boiler shall be operated at a higher pressure than the maxi- 
mum allowable working pressure except when the safety valve or 
valves are blowing, at which time the maximum allowable working 
pressure shall not be exceeded by more than 6 per cent. 

Wherever the term maximum allowable working pressure is used 
herein, it refers to gage pressure, or the pressure above the atmosphere, 
in pounds per square inch. 

180 The maximum allowable working pressure on the shell of a 
boiler or drum shall be determined by the strength of the weakest 
course, computed from the thickness of the plate, the tensile strength 
stamped thereon, as provided for in Par. 3'6, the efficiency of the 
longitudinal joint, or of the ligament between the tube holes in shell 
or drum, (whichever is the least), the inside diameter of the course, 
and the factor of the safety. 

TSXtXB 

— — == maximum allowable working pressure, lb. per sq. in. 

where 

TS <= ultimate tensile strength stamped on shell plates, as 
provided for in Par. 36, lb. per sq. in. 

i ■= minimum thickness of shell plates in weakest course, in. 

E =. efficiency of longitudinal joint or of ligaments between 
tube holes (whichever is the least) 

R = inside radius of the weakest course of the shell or 
drum, in. 

FS = factor of safety, or the ratio of the ultimate strength of 
the material to the allowable stress. For new con- 
structions covered in Part I, FS in the above for- 
mula = 5. 



44 report of boiler code committee, am.soc.m.b. 

Boiler Joints 

181 Efficiency of a Joint. The efficiency of a joint is the ratio 
which the strength of the joint bears to the strength of the solid 
plate. In the case of a riveted joint this is determined by calculating 
the breaking strength of a unit section of the joint, considering each 
possible mode of failure separately, and dividing the lowest result 
by the breaking strength of the solid plate of a length equal to that 
of the section considered. (See Appendix, Pars. 410 to 416, for 
detailed methods and examples.) 

182 The distance between the center lines of any two adjacent 
rows of rivets, or the *'back pitch'' measured at right angles to the 
direction of the joint, shall have the following minimum values : 

P . 

a If — is 4 or less, the minimum value shall be 2 D ; 
D ' 

p 

h If — is over 4, the minimum value shall be : 
D 



where 



2i) + 0.1 (P-4i>) 



p =: pitch of rivets in outer row where a rivet in the inner 
row comes midway between two rivets in the outer 
row, in. 

P =z pitch of rivets in the outer row less pitch of rivets in 
the inner row where two rivets in the inner row come 
between two rivets in the outer row, in. (It is here 
assumed that the joints are of the usual construction 
where the rivets are symmetrically spaced). 

D = diameter of the rivet holes, in. 

183 On longitudinal joints, the distance from, the centers of 
rivet holes to the edges of the plates, except rivet holes in the 
ends of butt straps, shall be not less than 1% and not more than 
1% times the diameter of the rivet holes; this distance to be 
measured from the center of the rivet holes to the calking edge of 
the plate before calking. The plate edge shall be beveled to an 
angle not sharper than 70 deg. to the plane of the plate and as 
near thereto as practicable. 

184 a Circumferential Joints. The strength of circumfer- 
ential joints of boilers, the heads of which are not stayed by tubes 
or through braces, shall be at least 50 per cent of that required for 
the longitudinal joints of the same structure. 

h When 50 per cent or more of the load which would act on an 
unstayed solid head of the same diameter as the shell, is relieved by 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 



45 



the effect of tubes or through stays, in consequence of the reduction 
of the area acted on by the pressure and the holding power of the 
tubes and stays, the strength of the circumferential joints in the 
shell shall be at least 35 per cent of that required for the longi- 
tudinal joints. 

c In the portion of circumferential joints of horizontal return 
tubular boilers, exposed to the products of combustion, the shearing 
strength of the rivets shall be not less than 50 per cent of the full 
strength of the plate corresponding to the thickness at the joint. 

185 When shell plates exceed 9/16 in. in thickness in horizontal 
return tubular boilers, the portion of the plates forming the laps of 
the circumferential joints, where exposed to the fire or products of 
combustion, shall be planed or milled down as shown in Fig. 8, to 
% in. in thickness, provided the requirement in Par. 184 is complied 
with. 




Fig. 8 Circumferektial Joint for Thick Plates of Horizontal Eeturn 

Tubular Boilers 

186 Welded Joints. The ultimate strength of a joint which 
has been properly welded by the forging process, shall be taken as 
28,500 lb. per sq. in., with steel plates having a range in tensile 
strength of 45,000 to 55,000 lb. per sq. in. Autogenous welding 
may be used in boilers in cases where the strain is carried by other 
construction which conforms to the requirements of the Code and 
where the safety of the structure is not dependent upon the strength 
of the weld. 

187 Riveted Longitudinal Joints. The riveted longitudinal 
joints of a shell or drum which exceeds 36 in. in diameter, shall 
be of butt and double-strap construction. This rule does not apply 
to the portion of a boiler shell which is staybolted to the firebox 
sheet. 

188 The longitudinal joints of a shell or drum which does not 
exceed 36 in. in diameter, may be of lap-riveted construction ; but 



46 



REPORT OP BOILER CODE COMMITTEE, AM.SOC.M.E. 



the maximum allowable working pressure shall not exceed 100 lb. 
per sq. in. 

189 The longitudinal joints of horizontal return tubular boilers 
shall be located above the fire-line of the setting. 

190 In horizontal return tubular boilers with lap joints, no 
course shall be over 12 ft. long. With butt and double strap con- 
struction longitudinal joints of any length may be used, provided 
the tension test specimens are so cut from the shell plate that their 
lengthwise direction is parallel with the circumferential seams of 
the boiler, and the tests meet the standards prescribed in the 
specifications for boiler plate steel. 

191 Butt straps and the ends of shell plates forming the longi- 
tudinal joints shall be rolled or formed by pressure, not blows, to 
the proper curvature. 

Ligaments 

192 Efficiency of Ligament When a shell or drum is drilled for 
tubes in a line parallel to the axis of the shell or drum, the efiaciency 
of the ligament between the tube holes shall be determined as follows : 

a When the pitch of the tube holes on every row is equal (Fig. 
9), the formula is: 

J- = efficiency of ligament 



where 



p = pitch of tube holes, in. 
d = diameter of tube holes, in. 










'€>-0^^-^-Q>^0-O- 



Lonojifuolinal Lfne ^ 

FlG. 9 Example of Tube Spacing with Pitch op 
Holes Equal in Every Eow; 



Example: Pitch of tube holes in the drum as shown in Fig. 9 
= 51/4 in. Diameter of tubes = 314 in. Diameter of tube holes = 
3 9/32 in. 



p—d 5.25— 3.,281 



5.25 



0.375, efficiency of ligament 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 



47 













i.onc[ifuciinc*l Line ' ■ > 

Pig. 10 Example of Tube Spacing with Pitch 
OF Holes Unequal in Every Second Eow 

h Wlien the pitch of tube holes on any one row is unequal (as 
in Figs. 10 or 11), the formula is: 

i_ . = efficiency of ligament 

p = unit length of ligament, in. 

n = number of tube holes in length, p, 

d = diameter of tube holes, in. 

Example: iSpacing shown in Fig. 10. Diameter of tube holes = 
3 9/32 in. 

p—nd 12—2X3.281 

— = O.MS, efficiency of ligament 



where 



P 



12 



Example: Spacing shown in Fig. 11. Diameter of tube holes 
= 3 9/32 in. 



p—nd 29.25—5X3.281 



P 



29.25 



^ 0.439, efficiency of ligament 






o 






<-5i% 







-eaV- 



Lonofitucf/nff/ Line 



Fig. 11 Example of Tube Spacing with Pitch of Holes 
. Varying in Every Second and Third Eow 

c The strength of those ligaments between the tube holes which 
are subjected to a longitudinal stress shall be at least one-half the 
required strength of those ligaments v^hieh come between the tube 
holes which are subjected to a circumferential stress. 



48 



REPORT OP BOILER CODE COMMITTEE, AM.SOC.M.B. 



193 When a shell or drum is drilled for tube holes so as to 
form diagonal ligaments as shown in Fig. 12, the efficiency of these 
ligaments shall be, that given by the diagram, Fig. 13. 

In this diagram the abscissae are —r- and the ordinates — , where 

p = longitudinal pitch of tube holes, or distance between 

centers of tubes in a longitudinal row, in. 
p' ^= diagonal pitch of tube holes, in. 
d = diameter of tube holes, in. 

To use the diagram. Fig. 13, the values of —- and — are com- 

d p 




Longitudinal Line 



Fig. 12 Example of Tube Spacing with Tube Holes on Diagonal Lines 

puted and the efficiency for the corresponding point is read off from 
the diagram. Should the point fall above the curve of equal 
efficiency for the diagonal and longitudinal ligaments, the longi- 
tudinal ligaments will be the weaker, in which case the efficiency 
is computed from the following formula: 

p — d 



(1) 



V 



Examples: 1st, diagonal pitch of tube holes in drum as shown 
in Fig. 12 — 6.42 in. 

Diameters of holes = 4 %2 iii- 
Longitudinal pitch of tube holes = lli/^ in. 

p _ 11.5 



d 
P 



4.031 

6.42 

11.5 



-= 2.853 



= 0.558 



p 




'W: 



0.9 



C.8- 



'i^i 



(C^c 






I 







7.2 /.3 .J.4 .1.5 ./.e .1.7 i/.8 



IIS .ZO Zl 22 £3 M- ££ iS.6 £.7 .^B 2.9 3.0 

■P 



3.2 3.d 3A 3.5 3B 5.7 38 3B 40 -4,1 d£ uL3 



.46 4.6 47 AS 49 SO 



—J — Pio. 13 DiAQR-vu FOB Determination of the Efficiencies op Lokgitudinal 

Cf .Ijqaments Between Tube Holes in Cylindrical Tube Siiee' 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 49 

The point corresponding to these values is shown at A on the 
diagram, Fig. 13, and the corresponding efficiency is 35.3 per cent. 
As the point falls below the curve of equal efficiency for the diag- 
onal and) longitudinal ligaments, the diagonal ligament is the 
weaker. 

2d, diagonal pitch of tube holes in drum=:6 3%4 in. 
Diameter of tube holes=4%4 in. 
Longitudinal pitch of tube holes ==7 in. 



P _ 



d 4.0156 
p' __ 6.547 



1.743 
0.935 



The point corresponding to these values is shown at B, and it 
will be seen that it falls above the line of equal efficiency for the 
diagonal and longitudinal ligaments, in which case the efficiency 
is computed from formula (1). Applying formula (1), we have 

=^ =: 0.426, efficiency of ligament, or 42.6 per cent. 

194 Domes. The longitudinal joint of a dome 24 in. or over 
in diameter shall be of butt and double-strap construction, irre- 
spective of pressure. When the maximum allowable working 
pressure excecxis 100 lb. per sq. in., the flange of a dome 24 in. or 
over in diameter shall be double-riveted to the boiler shell. 

The longitudinal joint of a dome less than 24 in. in diameter may 
be of the lap type, and its flange may be single-riveted to the boiler 
shell provided the maximum allowable working pressure on such a 
dome is computed with a factor of safety of not less than 8. 

The dome may be located on the barrel or over the fire-box on 
traction, portable or stationary boilers of the locomotive type up to 
and including 48 in. barrel diameter. For larger barrel diameters, 
the dome shall be placed on the barrel. 

Flanges of domes shall be formed with a corner radius, measured 
on the inside, of at least twice the thickness of the plate for plates 
1 in. thick or less, and at least three times the thickness of the 
plate for plates over 1 in. in thickness. 

Dished Heads 

195 Convex Beads. The thickness required in an unstayed 
dished head with the pressure on the concave side when it is a seg- 



50 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

ment of a sphere, shall be calculated by the following formula: 

5.5XPXL 

*- 2XTS +^8 
where 

t =: thickaess of plate, in. 

P = maximum allowable working pressure, lb. per sq. in. 

TS = tensile strength, lb. per sq. in. 

L = radius to which the head is dished, in. 

Where two radii are used the longer shall be taken as the value 
of L in the formula. 

Where the radius is less than 80 per cent of the diameter of the 
shell or drum to which the head is attached the thickness shall be at 
least that found by the formula by making L equal to 80 per cent of 
the diameter of the shell or drum. 

Concave Heads. Dished heads with the pressure on the convex 
side shall have a maximum allowable working pressure equal to 60 
per cent of that for heads of the same dimensions with the pressure 
on the concave side. 

When a dished head has a manhole opening, the thickness as 
found by these Rules shall be increased by not less than 1/8 in. 
over that called for by the formula. Where a dished head has a 
flanged opening supported by an attached flue, the increase of 
ji in. in thickness is not required. 

196 When dished heads are of a less thickness than called for 
by Par, 195, they shall be stayed as flat surfaces, no allowance being 
made in such staying for the holding power due to the spherical form. 

197 The corner radius of an unstayed dished head measured on 
the concave side of the head shall not be less than li^ in. or more 
than 4 in. and within these limits shall be not less than 3 per cent of 
L in Par. 195. 

198 A manhole opening in a dished head shall be flanged to a 
depth measured from the outside of not less than three times the 
required thickness of the head. 

Braced and Stayed Surfaces 

199 The maximum allowable working pressure for various 
thicknesses of braced and stayed flat plates and those which by 
these Rules require staying as flat surfaces with braces or staybolts 



NEW INSTALLATIONS, TART I, SECTION I, POWER BOILERS 51 

of uniform diameter symmetrically spaced, shall be calculated by 
tlie formula : 

J2 



P = CX 



wliere 



p2 



P = maximum allowable working pressure, lb. per sq. in. 

T = thickness of plate in sixteenths of an inch. 

p = maximum pitch measured between straight lines passing 
through the centers of the staybolts in the different 
rows, which lines may be horizontal, vertical or in- 
clined, in. 

C = 112 for stays screwed through plates not over 7/16 in. 
thick with ends riveted over 

C = 120 for stays screwed through plates over 7/16 in. thick 
with ends riveted over 

C = 135 for stays screwed through plates and fitted with 
single nuts outside of plate 

C = 150 for stays with heads not less than 1.3 times the 
diameter of t^,s stays, screwed through plates or made 
a taper fit and having the heads formed on the stays 
before installing them and not riveted over, said heads 
being made to have a true bearing on the plate. 

C = 175 for stays fitted with inside and outside nuts and 
outside washers where the diameter of washers is not 
less than OAp and thickness not less than T. 

If a flat boiler plate not less than % in. thick is strengthened 
with a doubling plate covering the full area of the stayed surface 
and securely riveted thereto and having a thickness of not less than 
2/3 T, then the value of T in the formula shall be three-quarters 
of the com.bined thickness of the boiler plate and doubling plate 
but not more than one and one-half times the thickness of the 
boiler plate, and the value of C given above ma^ also be incrcas^^i 
15 per cent. 

When two sheets are connected by stays and but one of these 
sheets requires staying, the value of C is governed by the thickness 
of the sheet requiring staying. 



52 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



Acceptable proportions for the ends of through stays with 
washers are indicated in Fig. 14. 

200 Stayholts. The ends of screwed staybolts shall be riveted 
over or upset by equivalent process. The outside ends of solid 
staybolts, 8 in. and less in length, shall be drilled with a hole at 
least 3/16 in. diameter to a depth extending at least 1/2 in. beyond 
the inside of the plates, or hollow staybolts may be used. On 
boilers having a grate area not exceeding 15 sq. ft., or the equivalent 
in gas- or oil-fired boilers, the drilling of staybolts is optional. Solid 
staybolts over 8 in. long, and flexible staybolts of either the jointed 
or ball-and-socket type, need not be drilled. Staybolts used in 



Not Less fhan 
ZjDiamefers 
ofBoltbufmu. 
bf 0.4 Pitch 
ofSfatjs ff 
C=n5 




NofLess-fhanjt 
i-f C=I50 or Less, 
and not Less than i 
if C'llS. 



Fig. 14 Acceptable Proportions for 
Ends of Through Stays 



waterlegs of water-tube boilers shall be hollow or drilled at both 
ends, irrespective of their length. 

201 Biructural 'Reinforcements. "When channel irons or other 
members are securely riveted to the boiler heads for attaching 
through stays, the transverse stress on such members shall not 
exceed 12,500 lb. per sq. in. In computing the stress, the section 
modulus of the member shall be used without addition for the 
strength of the plate. The spacing of the rivets over the supported 
surface shall be in conformity with that specified for staybolts. 

If the outstanding legs of the two members are fastened 
together so that they act as one member in resisting the bending 
action produced by the load on the rivets attaching the members 
to the head of the boiler, and provided that the spacing of these 
rivets attaching the members to the head is approximately uniform, 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 53 

the members may be computed as a single beam uniformly loaded 
and supported at the points where the through braces are attached. 

202 Stays. The ends of stays fitted with nuts shall not be 
exposed to the direct radiant heat of the fire. 

203 a The maximum spacing between centers of rivets or 
between the edges of tube holes and the centers of rivets attaching 
the crowfeet of braces to the braced surface, shall be determined 
as in Par. 199, using 135 for the value of C. 

h The maximum distance between the edges of tube holes and 
the centers of other tj^es of stays shall be determined by the 
formula in Par. 199, using the value of C given for the thickness 
of plate and type of stay used. 

c The maximum spacing between the inner surface of the shell 
and lines parallel to the surface of the shell passing through the 
centers of the rivets attaching the cro^vfeet of braces to the head, 
shall be determined by the formula in Par. 199, using 175 for the 
value of C, 

d The maximum distance between the inner surface of the 
shell and the centers of braces of other types shall be determined 
by the formula in Par. 199, using a value of C equal to 1.3 times 
that value of C which applies to the thickness of plate and type 
of stay as therein specified. 

€ In applying these Rules and those in Par. 199 to a head or 
plate having a manhole or reinforced opening, the spacing applies 
only to the plate around the opening and not across the opening. 

204 The formula in Par. 199 was used in computing Table 4. 
"Where values for screwed stays with ends riveted over are required 
for conditions not given in Table 4, they may be computed from the 
formula and used, provided the pitch does not exceed 8% in. 

205 The distance from the edge of a staybolt hole to a straight 
line tangent to the edges of the rivet holes may be substituted for p 
for staybolts adjacent to the riveted edges bounding a stayed surface. 
When the edge of a stayed plate is flanged, p shall be measured from 
the inner surface of the flange, at about the line of rivets to the 
edge of the staybolts or to the projected edge of the staybolts. 

206 The distance between the edges of the staybolt holes may 
be substituted for p for staybolts adjacent to a furnace door or other 
boiler fitting, tube hole, handhole or other opening. 



54 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



TABLE 4 MAXIMUM ALLOWABLE PITCH, IN INCHES, OF SCREWED STAY- 
BOLTS, ENDS RIVETED OVER 





Thickness of Plate, In. 


Pressure, 
Lb. per Sq. In. 


A 


% 


^ 


1/2 


^ff %^ 


1* 


Maximum Pitch of Staybolts, In. 


100 


5 

4% 
4% 
41/2 
41/4 
41/8 
4 


6% 

6 

5% 

5% 

51/2 

5% 

5y8 
5 

4% 
4^ 
4% 
41/2 
41^ 
4 


7% 
7 

6% 
6% 

61/2 
61/4 

6 

578 
5% 
51^ 
5% 
51^ 
47/8 
4% 
41/4 










110 


8% 

8 

1% 

7% 

7% 

7% 

6% 

6% 

6 1/2 

6% 

61/8 
5 78 

51/2 
5 








120 








125 








130 








140 


8% 
8 

7% 
7 72 
7% 
71/8 

6 72 

6% 
5% 






150 






160 






170 
180 
190 

200 
225 
250 
300 


8% 
878 

7 78 
1% 
7 74 

6 78 

61^ 


8 72 

8 

7% 
7 











For the application of Pars. 205 and 206, see Fig. 32 in the Appendix. 

207 In water leg boilers, the staybolts may be spaced at greater 
distances between the rows than indicated in Table 4, provided the 
portions of the sheet which come between the rows of staybolts have 
the proper transverse strength to give a factor of safety of at least 
5 at the maximum allowable working pressure. 

208 The diameter of a screw stay shall be taken at the bottom 
of the thread, provided this is the least diameter. 

209 The least cross-sectional area of a stay shall be taken in 
calculating the allowable stress., except that when the stays are 
welded and have a larger cross-sectional area at the weld than at 
some other point, in which case the strength at the weld shall be 
computed as well as in the solid part and the lower value used. 

210 Holes for screw stays shall be drilled full size or punched 
not to exceed 1/4 i^* l^^s than full diameter of the hole for plates over 
5/16 in. in thickness, and % in. less than the full diameter of the 
hole for plates not exceeding 5/16 in. in thickness, and then drilled 
or reamed to the full diameter. The holes shall be tapped fair and 
true, with a full thread. 

211 The ends of steel stays upset for threading, shall be thor- 
oughly annealed. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 55 

212 a The maximum allowable working pressure for any 
curved stayed surface subject to internal pressure shall be obtained 
by the two following methods, and the minimum value obtained 
shall be used: 

First, the maximum allowable working pressure shall be computed 
without allowing for the holding power of the stays, due 
allowance being made for the weakening effect of the holes for 
the stays. To this pressure there shall be added the pressure 
secured by the formula for braced and stayed surfaces given 
in Par. 199, using 70 for the value of C. 

Second, the maximum allowable working pressure shall be computed 
without allowing for the holding power of the stays, due allow- 
ance being made for the weakening effect of the holes for the 
stays. To this pressure there shall be added the pressure cor- 
responding to the strength of the stays for the stresses given 
in Table 5, each stay being assumed to resist the steam pressure 
acting on the full area of the external surface supported by the 
stay. 

h The maximum allowable working pressure for a stayed wrap- 
per sheet of a locomotive-type boiler shall be determined by the 
two methods given above and by the method which follows and the 
minimum value obtained shall be used: 

11 OOO^X^ 



i? — s S sin oc 
in which 

oc nr angle any crown stay makes with vertical axis of boiler 

2 sin oc = summated value of sin oc for all crown stays considered 

in one transverse plane and on one side of vertical axis 

of boiler 

s = transverse spacing of crown stays in crown sheet, in. 

E = minimum efficiency of wrapper sheet through joints or 

stay holes 
i = thickness of wrapper sheet, in. 
E = radius of wrapper sheet, in. 
P =r working pressure of boiler, lb. per sq. in. 
11 000 = allowable stress, lb. per sq. in. 
c A cylindrical furnace which requires staying shall be stayed 
as a flat surface as indicated in Table 4, except that the pitch may 



56 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



be increased to pi, as provided in the following formula 



PR 



PB — 250r 
in which 

Pi = equivalent pitch for a cylindrical surface. 

p zzz maximum pitch for a flat surface measured as specified 

in Par. 199. 
P=: maximum allowable working pressure, lb. per sq, in. 
B = internal radius of furnace, in. 
T = thickness of plate in sixteenths of an inch., 

213 Staying Segments of Heads. A segment of a head shall 
be stayed by head to head, through, diagonal, crowfoot or gusset 




Fig. 15 Method of Determining Net Aeea of Segment of a Head 

stays, except that a horizontal return tubular boiler may be stayed 
as provided in Pars. 225 to 229. 

214 Areas of Heads to he stayed. The area of a segment of a 
head to be stayed shall be the area enclosed by lines drawn 2 in. 
from the tubes and at a distance d from the shell as shown in Figs. 15 
and 16. The value of d used may be the larger of the following 
values : 

(1) d = the outer radius of the flange, not exceeding 8 times 
the thickness of the head 

5Xr 



(2) 



d = 



Si P 



where d = unstayed distance from shell in inches 

T = thickness of head in sixteenths of an inch 

P = maximum allowable working pressure in lb. per sq. in. 



NEW INSTxiLLATIONS, PART I, SECTION I, POWER BOILERS 57 

In water-tube boilers, the tubes of which are connected to drum 
heads, the area to be stayed shall be taken as the total area of the 
head less the area of an annular ring of width d measured from 
the inner circumference of the drum shell. 

215 When the tube heads of drums of water-tube boilers are 
30 in. or less in diameter and the tube plate is stiffened by flanged 
ribs or gussets, no stays need be used if a hydrostatic test to destruc- 
tion of a boiler or unit section built in accordance with the con- 
struction, shows that the factor of safety is at least five. 

216 Stays shall be used in the tube sheets of a fire-tube boiler 
if the distance between the edges of the tube holes exceeds the 
maximum pitch of staybolts for the corresponding plate thickness 




Fig. 16 Method of Determining Net Area of Irregular 
Segment of a Head 

and pressure given in Table 4. That part of the tube sheet which 
comes between the tubes and the shell need not be stayed, if the 
distance to the nearest tangent common to two tube holes when 
measured on any radius of the tube sheet that intersects the tangent 
between the holes, does not exceed this maximum pitch by more 
than 3 in. The tube holes to which a common tangent may be 
drawn in applying this rule shall not be at a greater distance from 
edge to edge than the maximum pitch referred to. 

217 The net area to be stayed in a segment of a head may be 
determined by the following formula : 



^ J / V ; — 0.608 = area to be stayed, sq. in. 



3 \ {H-d-2) 

where 

II z= distance from tubes to shell, in. 
d = distance given by formula in Par. 214. 
E — radius of boiler head, in. 



58 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

218 When the portion of the head below the tubes in a horizon- 
tal return tubular boiler is provided with a manhole opening, the 
flange of which is formed from the solid plate and turned inward 
to a depth of not less than three times the required thickness of the 
head, measured from the outside, the area to be stayed as indicated 
in Fig. 16, may be reduced by 100 sq. in. The surface around the 
manhole shall be supported by through stays with nuts inside and 
outside at the front head. 

The distance in the clear between the bodies of the braces, or 
of the inside braces where more than two are used, shall not be less 
than 10 in. at any point. 

219 "When stay rods are screwed through the sheets and riveted 
over, they shall be supported at intervals not exceeding 6 ft. In 
boilers without manholes, stay rods over 6 ft. in length may be 
screwed through the sheets and fitted with nuts and washers on 
the outside. 

220 a The full pitch dimensions of the stays shall be em- 
ployed in determining the area to be supported by a stay, and the 
area occupied by the stay shall be deducted therefrom to obtain 
the net area. The product of the net area in square inches by the 
maximum allowable working pressure in lb. per sq. in., gives the 
load to be supported by the stay. 

t Where stays come near the outer edge of the surfaces to be 
stayed and special allowances are made for the spacing, the load 
to be carried by such stays shall be determined by neglecting the 
added area provided for by these special allowances. For example, 
if the minimum pitch by Table 4 would make a staybolt come 6 in. 
from the edge of the plate and a special allowance would make it 
come 7 in., the distance of 6 in. should be used in computing the 
load to be carried. 

c The maximum allowable stress per square inch at point of 
least net cross-sectional area of stays and staybolts shall be as given 
in Table 5. In determining the net cross-sectional area of drilled 
or hollow staybolts, the cross-sectional area of the hole shall be 
deducted. 

d The length of the stay between supports shall be measured 
from the inner faces of the stayed plates. The stresses are based on 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 59 

TABLE 5 MAXIMUM ALLOWABLE STRESSES FOR STAYS AND 

STAYBOLTS 





Stresses, lb. per sq. in. 


Description of Stays 


For lengths between 
supports not exceed- 
ing 120 diameters 


For lengths between 

supports exceeding 

120 diameters 


a Unwelded or flexible stays less than twenty 
diameters long, screwed through plates 
with ends riveted ovei' 


7,500 
8,000 

9,500 

10,400 
6,000 




6 Hollow steel stays less than 20 diameters 
long, screwed through plates with ends 
riveted over 




c Unwelded stays and unwelded portions of 
welded stays, except as specified in line 
a and line h 

d Steel through stays exceeding IY2 in. diam- 
eter 

e Welded portions of stays 


8,500 

9,000 
6,000 



tension only. For computing stresses in diagonal stays, see Pars. 
221 and 222. 

221 Stresses in Diagonal and Gusset Stays. Multiply the area 
of a direct stay required to support the surface by the slant or 
diagonal length of the stay ; divide this product by the length of a 
line drawn at right angles to surface supported to center of palm 
of diagonal stay. The quotient will be the required area of the 
diagonal stay, 

aXL 



A = 



I 



where 

A = sectional area of diagonal stay, sq. in. 
a = sectional area of direct stay, sq. in. 
L = length of diagonal stay, as indicated in Fig. 17, in. 
I = length of line drawn at right angles to boiler head or 
surface supported to center of palm of diagonal stay, 
as indicated in Fig. 17. 
Example: Given diameter of direct stay = 1 in., a = 0.7854> 
L = 60 in., I = 48 in. ; substituting and solving: 

0.7854X60 



A = 



48 



= 0.981 sectional area, sq. in. 



Diameter ii:i 1.11 in. = ll^ in. 



60 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

222 For staying segments of tube sheets such as in horizontal 
return tubular boilers, where L is not more than 1.15 times I for any 
brace, the stays may be calculated as direct stays, allowing 90 per 
cent of the stress given in Table 5. 

223 Design of Braces and Brace Connections. All rivet and 
pin holes shall conform to the requirements in Par. 253 and the 
pins shall be made a neat fit. To determine the sizes that shall 
be used proceed as follows: 

1. Determine the '* required cross-sectional area of the brace'' by 

first computing the total load to be carried by the brace, and 
dividing the total load by the value of allowable stress for 
unwelded stays given in Table 5. 

2. Design the body of the brace so that the cross-sectional area 
shall be at least equal to the *' required cross-sectional area of 
the brace" for unwelded braces. Where the braces are 
welded, the cross-sectional area at the weld shall be at least 
as great as that computed for a stress of 6000 lb. per sq. in. 
(see Table 5). 

3. Make the area of pins to resist double shear at least three- 

quarters of the '* required cross-sectional area of the brace." 

4. Make the combined cross-section of the eye at the side of the 

pin (in crowfoot braces) at least 25 per cent greater than the 
*' required cross-sectional area of the brace." 

5. Make the cross-sectional areas through the blades of diagonal 

braces where attached to the shell of the boiler at least equal 
to the required rivet section ; that is, at least equal to one and 
one-quarter times the "required cross-sectional area of the 
brace. ' ' 

6. Design each branch of a crowfoot to carry two-thirds the total 
load on the brace. 

7. Make the net sectional areas through the sides of the crow- 
foot, tee irons, or similar fastenings at the rivet holes at least 
equal to the required rivet section, that is, at least equal to 
one and one-quarter times the ''required cross-sectional area 

of the brace. ' ' 

8. Make the combined cross-sectional area of the rivets at each 

end of the brace at least one and one-quarter times the ''re- 
quired cross-sectional area of the brace." 

224 Gusset stays when constructed of triangular right-angled 
web plates secured to single or double angle bars along the two 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 



61 



sides at right angles shall have a cross-sectional area (in a plane at 
right angles to the longest side and passing through the intersection 
of the two shorter sides) not less than 10 per cent greater than 
would be required for a diagonal stay to support the same surface, 
figured by the formula in Par. 221, assuming the diagonal stay is 
at the same angle as the longest side of the gusset plate. 

225 Staying of Upper Segments of Tiibe Heads hy Steel Angles. 
When the shell of a boiler does not exceed 36 in. in diameter and is 
designed for a maximum allowable working pressure not exceeding 
100 lb. per sq. in., the segment of heads above the tubes may be 
stayed by steel angles as specified in Table 6 and Fig. 18, except 
that angles of equal thickness and greater depth of outstanding 




Fig. 17 Measurements tor Determining Stresses in 
Diagonal Stays 

leg, or of greater thickness and the same or greater depth of out- 
standing leg, may be substituted for those specified. The legs at- 
tached to the heads may vary in depth }^ in. above or below the 
dimensions specified in Table 6. 

226 When this form of bracing is to be placed on a boiler, the 
diameter of which is intermediate to or below the diameters given 
in Table 6, the tabular values for the next higher diameter shall 
govern. Rivets of the same diameter as used in the longitudinal 
seams of the boiler shall be used to attach the angles to the head 
and to connect the outstanding legs. 

227 The rivets attaching angles to heads shall be spaced not 
over 4 in. apart. The centers of the end rivets shall be not over 3 
in. from the ends of the angle. The rivets through the outstanding 
legs shall be spaced not over 8 in. apart; the centers of the end 
rivets shall be not more than 4 in. from the ends of the angles. The 
ends of the angles shall be considered those of the outstanding legs 



62 



EEPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



and the lengths shall be such that their ends overlap a circle 3 in. 
inside the inner surface of the shell as shown in Fig. 18. 

228 The distance from the center of the angles to the shell of 
the boiler, marked A in Fig. 18', shall not exceed the values given in 
Table 6, but in no case shall the leg attached to the head on the lower 
angle come closer than 2 in. to the top of the tubes, 

229 When segments are beyond the range specified in Table 6, 
the heads shall be braced or stayed in accordance with the require- 
ments in these Rules. 




Pig. 18 Stating of Head with Steel Angles in Tubular Boiler 



TABLE 6 .SIZES OP ANGLES REQUIRED FOR STAYING- SEGMENTS OF HEADS 
With the short legs of the angles attached to the head of the boiler 



Height 

of 

Segment, 

Dimension B 


30-in. Boiler 


34-in. Boiler 


36-in. Boiler 




Angle 


Angle 


Angle 
4"x3" 


Angle 
3i^''x3'' 


Angle 
4"x3" 


Angle 
5"x3" 


Angle 
4"x3" 


Angle 
5"x3'' 


Angle 
6"x3y2" 


Dimen- 
sion 
A in 


in Fig. 18 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Thick- 
ness, 
inches 


Fig. 18 


10 
11 
12 
13 
14 
15 
16 


% 

9 
IS" 


1^ 
% 


% 




% 


1^ 
% 

V2 


% 


% 
% 


% 
% 


6^ 

7 

7% 

8 

8% 

9 

9^^ 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 63 

230 Crown Bars and Girder Stays. Crown bars and girder 

stays for tops of combustion chambers and back connections, or 

wherever used, shall be proportioned to conform to the following 

formula : 

Cy<(d^y(_t 
Maximum allowable working pressure =-7-777 — ttt — tt — ttt 

where 

W =z extreme distance between supports, in. 
P == pitch of supporting bolts, in. 

D = distance between girders from center to center, in. 
d = depth of girder, in. 
t = thickness of girder, in. 

C = 7000 when the girder is fitted with one supporting bolt 
C = 10,000 when the girder is fitted with two or three sup- 
porting bolts 
C = 11,000 when the girder is fitted with four or five sup- 
porting bolts 
C = 11,500 when the girder is fitted with six or seven sup- 
porting bolts 
C = 12,000 when the girder is fitted with eight or more sup- 
porting bolts 
Example: Given W = 34 in., P = 7.5 in., D — 7.75 in., 
d = 7.5 in., t = 2 in. ; three stays per girder, C = 10,000 ; then 
substituting in formula: 

Maximum allowable working pressure = 
10,000X7.5X7.5X2 -,..,,, 
(34-7.5) X7.75X34 = ^^^'^ ^^' ^"^ '^- ^^• 

231 Maximum Allowable Working Pressure on Truncated 
Cones. 

a Upper combustion chambers of vertical submerged tubular 
boilers made in the shape of a frustum of a cone when not over 38 
in. diameter at the large end, may be used without stays if computed 
by the rule for plain cylindrical furnaces (Par. 239) making D in 
the formula equal to the diameter at the large end; provided that 
the longitudinal joint conforms to the requirements of Par. 239. 

h When over 38 in. in diameter at the large end, that portion 
which is over 30 in. in diameter shall be fully supported by staj'- 
bolts or g-ussets to conform to the provisions for staying flat sur- 
faces. In this case the top row of staybolts shall be at a point 
where the cone top is 30 in. or less in diameter. 



64 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

In calculating the pressure permissible on the unstayed portion 
of the cone, the vertical distance between the horizontal planes 
passing through the centers of the rivets at the cone top, and 
through the center of the top row of staybolts shall be used as L 
in Par. 239, and D in that paragraph shall be the inside diameter 
at the center of the top row of staybolts. 

232 Stay Tubes. "When stay tubes are used in multitubular 
boilers to give support to the tube plates, the sectional area of such 
stay tubes may be determined as follows : 

rr. , . ^ •, . \A~a) P 
Total section of stay tubes, sq. m. = jj^ — 

where 

A = area of that portion of the tube plate containing the 

tubes, sq. in. 
a = aggregate area of holes in the tube plate, sq. in. 
P = maximum allowable working pressure, lb. per sq. in. 
T8 = working tensile stress allowed in the tubes, not to 
exceed 7000 lb. per sq. in. 

233 The pitch of stay tubes shall conform to the formula given 
in Par. 199, using the values of C as given in Table 7. 

When the ends of tubes are not shielded from the action of flame 
or radiant heat, the values of G shall be reduced 20 per cent. The 
tubes shall project about % in. at each end and be slightly flared. 
Stay tubes when" threaded shall not be less than 3/16 in. thick at 
bottom of thread; nuts on stay tubes are not advised. For a nest 
of tubes C shall be taken as 140 and S as the mean pitch of stay 
tubes. For spaces between nests of tubes ;S' shall be taken as the 
horizontal distance from center to center of the bounding rows of 
tubes and C as given in Table 7. 

TABLE 7 VALUES OF C FOR DETERMINING PITCH OP STAY TUBES 



Pitch of Stay Tubes in the Bounding Rows 


When tubes 

have no Nuts 

outside of Plates 


When tubes 

are Pitted with 

Nuts outside 

of Plates 


Where there are two plain tubes between each stay tube. 

Where there is one plain tube betAveen each stay tube. . 

Where every tube in the bounding rows is a stay tube 

and each alternate tube has a nut 


120 
140 


130 
150 

170 



new installations, part i, section i, power boilers «5 

Tube Sheets of Combustion Chambeps 

234 The maximum allowable working pressure on a tube sheet 
of a combustion chamber, where the crown sheet is not suspended 
from the shell of the boiler, shall be determined by the following 
formula : 

(D-d) ^X27,00Q 

^-' WXD 

where 

P = maximum allowable working pressure, lb. per sq. in. 
D =z least horizontal distance between tube centers on a 

horizontal row, in. 
d = inside diameter of tubes, in. 
t =z thickness of tube plate, in. 

W = distance from the tube sheet to opposite combustion 
chamber sheet, in. 

Where tubes are staggered the vertical distance between the 
center lines of tubes in adjacent rows must be not less than 

y2V2dD+d^ 

Example: Required the working pressure of a tube sheet sup- 
porting a crown sheet braced by crown bars. Horizontal distance 
between centers, 4% in. ; inside diameter of tubes, 2.782 in. ; thick- 
ness of tube sheets, 11/16 in. ; distance from tube sheet to opposite 
combustion-chamber sheet, 3414 in-? measured from outside of tube 
plate to outside of back plate; material, steel. Substituting and 
solving : 

^ (4.125-2.782) X0.6875X27,000 ^_ ., 

235 Sling stays may be used in place of girders in all cases 
covered in Par. 234, provided, however, that when such sling sitays 
are used, girders or screw stays of the same sectional area shaU be 
used for securing the bottom of the combustion chamber to the 
boiler shell. 

236 When girders are dispensed with and the top and bottom 
of combustion chambers are secured by sling stays or braces, the 
sectional area of such stays shall conform with the requirements of 
rules for stays and stayed surfaces. 

237 Furnaces of Vertical Boilers. In a vertical fire-tube boiler 
the furnace length, for the purpose of calculating its strength and 
spacing staybolts over its surface, shall be measured from the center 
of rivets in the bottom of the water-leg to the center of rivets in 
the flange of the lower tube sheet. 



66 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

238 When the longitudinal joint of the furnace sheet of a verti- 
cal fire-tube boiler is of lap-riveted construction and staybolted, a 
staybolt in each circular row shall be located near the longitudinal 
joint, as shown in Fig. 19. 

239 Plain Circular Furnaces. Unstayed furnaces more than 
12 in. diameter when riveted, of seamless construction, or when lap 
welded by the forging process, shall have walls not less than 5/16 
in. thick. The maximum allowable working pressure for such 
furnaces, from 12 in. to 18 in. diameter inclusive, and of a length 
not more than four and one-half diameters ; also for furnaces more 
than 18 in. diameter and not exceeding 38 in. diameter, shall be 
determined by one or the other of the following formulae: 




Fig. 19 Proper Location of Staybolts Adjacent to Longitudinal 

Joint in Furnace Sheet 

a Where the* length does not exceed 120 times the thickness 

of the plate 

51 5 C "i 

P = -^-\ (18.75xr)-(1.03Xi)| 

h Where the length exceeds 120 times the thickness of the 
plate 

4250 X^^ 



P = 



where 



LXD 



P = maximum allowable working pressure, lb. per sq. in. 

D = outside diameter of furnace, in. 

L = total length of furnace between centers of head rivet 

seams (not length of a section), in. 
T = thickness of furnace walls, in sixteenths of an inch. 

In determining the maximum allowable working pressure for 
unstayed furnaces more than 18 in. diameter and not exceeding 38 
in. diameter, if over six diameters in length, L in the formula shall 
be taken as six times the diameter. 

Example: Given a furnace 26 in. diameter, 94 in. long and 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 67 

% in, thick. The length exceeds 120 times the thickness of the 
plate, hence formula (&) should be used. Substituting the values 
in this formula: 

~ — 94X26 ^- P^^ ^^' ^^• 

Where an unstayed furnace has a riveted longitudinal joint, it 
may be of the lap type for inside diameters not exceeding 30 in., 
irrespective of the height or length of the furnace. For inside 
diameters not exceeding 36 in., a riveted longitudinal joint may be 
of the lap type provided the furnace does not exceed 36 in. in height 
or length. Otherwise butt and single or double strap construction 
shall be used. The efficiency of the joint shall be greater than ; 

PXD 
1250 X T 
Unstayed furnaces of 12 in. to 18 in. diameter inclusive, if over 
four and one-half diameters in length, shall be considered as iiues, 
and shall be governed by Par. 241. 

240 A plain cylindrical furnace exceeding 38 in. diameter shall 
be stayed- in accordance with the rule in Par. 212 c. 

241 Circular Flues. The maximum allowable working pressure 
for seamless or welded flues more than 5 in. diameter and up to and 
including 18 in. diameter shall be determined by one or the other 
of the following formulae: 

a Where the thickness of the wall is less than 0.023 times the 
diameter 

p_ 10,000,000 X^^ 

h Where the thickness of the wall is greater than 0.023 times 
the diameter 

p ^ 17,300X^ o^g 

P = maximum allowable working pressure, lb. per sq. in. 
D = outside diameter of flue, in. 
t = thickness of wall of flue, in. 
The above formulae may be applied to riveted flues of the 
sizes specified provided the sections are not over 3 ft. 
in length and provided the efficiency of the joint is 
greater than PXD divided by 20,000 X^. 



where 



68 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

Example: Given a flue 14 in. in diameter and 5/16 in. thick. 
The thickness of the wall is less than 0.023 times the diameter; 
hence formula (a) should be used. Substituting the values in this 
formula : 

J, 10,000,000X5/16X5/16X5/16 ,,. ., 

P = 14X14X14 ~ ^^^ ^^' ^^' 

242 Adamson Type. "When plain horizontal flues are made in 
sections not less than 18 in. in length, and not less than 5/16 in. 
thick : 

a They shall be flanged with a radius measured on the fire side, 
of not less than three times the thickness of the plate, and the flat 
portion of the flange outside of the radius shall be at least three 
times the diameter of the rivet holes. 

h The distance from the edge of the rivet holes to the edge of 
the flange shall be not less than the diameter of the rivet hole, and 
the diameter of the rivets before driving shall be at least % in. 
larger than the thickness of the plate. 

c The depth of the Adamson ring between the flanges shall be 
not less than three times the diameter of the rivet holes, and the 
ring shall be substantially riveted to the flanges. The fire edge 
of the ring shall terminate at or about the point of tangency to the 
curve of the flange, and the thickness of the ring shall be not less 
than % in. 

The maximum allowable working pressure shall be determined 
by the following formula: 



P = ^(^{mi5XT)-{lMXL)'j 



where 

P = maximum allowable working pressure, lb. per sq. in. 
P =1 outside diameter of furnace, in. 
L = length of furnace section, in. 
T = thickness of plate, in sixteenths of an inch. 
Example: Given a furnace 44 in. in diameter, 48 in. in length, 
and % in. thick. Substituting values in formula: 

= 1.309 (150-49.44) = 131 lb. per sq. in. 
243 The maximum allowable working pressure on corrugated 
furnaces, such as the Leeds suspension bulb, Morison, Fox, Purves, 
or Brown, having plain portions at the ends not exceeding 9 in. in 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 69 

length (except flues especially provided for) when new and prac- 
tically circular, shall be computed as follows: 

p_CXt 

where 

P = maximum allowable working pressure, lb. per sq. in. 
t = thickness, in. — not less than 5/16 in. for Leeds, Morison, 
Fox and Brown, and not less than 7/16 in. for Purves 
and other furnaces corrugated by sections not over 18 
in. long, 
D = mean diameter, in. 

C =: 17,300, a constant for Leeds furnaces, when corrugations 
are not more than 8 in. from center to center and not 
less than 2i/4 iii- deep. 
C = 15,600, a constant for Morison furnaces, when corruga- 
tions are not less than 8 in. from center to center and 
the radius of the outer corrugations is not more than 
one-half that of the suspension curve. 
C = 14,000, a constant for Fox furnaces, when corrugations 
are not more than 8 in. from center to center and not 
less than 1% in. deep. 
C ^= 14,000, a constant for Turves furnaces when rib projec- 
tions are not more than 9 in. from center to center and 
not less than 1% in. deep. 
€ = 14,000, a constant for Brown furnaces, when corruga- 
tions are not more than 9 in. from center to center and 
not less than 1% in. deep. 
1(7 = 10,000, a constant for furnaces corrugated by sections 
not more than 18 in. from center to center and not less 
than 21/2 i^^- deep, measured from the least inside to 
the greatest outside diameter of the corrugations, and 
having the ends fitted one into the other and substan- 
tially riveted together, provided that the plain parts 
at the ends do not exceed 12 in. in length. 
In calculating the mean diameter of the Morison furnace, the 
least inside diameter plus 2 in., may be taken as the mean diameter. 
244 The thickness of a corrugated or ribbed furnace shall be 
ascertained by actual measurement. The furnace shall be drilled 
for a %-in. pipe tap and fitted with a screw plug that can be re- 
moved for the purpose of measurement. For the Brown and Purves 



70 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

furnaces, the holes shall be in the center of the second flat; for the 
Morison, Fox and other similar types, in the center of the top cor- 
rugation, at least as far in as the fourth corrugation from the end 
of the furnace. 

245 Cast-iron and Malleahle-Iron Headers, The pressure al- 
lowed on a water-tube boiler shall not exceed 160 lb. per sq. in. 
when the tubes are secured to cast-iron headers, nor 200 lb. when 
the tubes are secured to malleable-iron headers. The form and size 
of the internal cross-section perpendicular to the longer axis of a 
cast-iron or malleable-iron header at any point shall be such that 
it will fall within a 7 in. by 7 in. rectangle. 

246 a The cast-iron used for the headers of water-tube boilers 
shall conform to the Specifications for Gray-Iron Castings given in 
Pars. 95 to 110, the header to be arbitrarily classified as a ** medium 
casting'' as to physical properties and tests, and as a ''light casting'' 
as to chemical properties. 

h A cast-iron header when tested to destruction, shall withstand 
a hydrostatic pressure of at least 1200 lb. per gq. in. and a malleable 
iron header, 1500 lb. A hydrostatic test at 400 lb. per sq. in. for 
cast iron and 500 lb. per sq. in. for malleable iron shall be made on 
all new headers with tubes attached. 

247 Where it is impossible to calculate with a reasonable 
degree of accuracy the strength of a boiler structure or any part 
thereof, a full-sized sample shall be built by the manufacturer 
and tested to destruction in the presence of the Boiler Code Com- 
mittee or one or more representatives of the Boiler Code Committee 
appointed to witness such test. 

Tubes 

248 Tube Holes and Ends. Tube holes shall be drilled full 
Size from the solid plate, or they may be punched at least %> ^^^ 
smaller in diameter than full size, and then drilled, reamed or 
finished full size with a rotating cutter. 

249 The sharp edges of tube holes shall be taken off on both 
sides of the plate with a file or other tool. 

250 A fire-tube boiler shall have both ends of the tubes sub- 
stantially rolled and beaded ; or rolled and welded at the firebox 
or combustion-chamber end. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 



71 



251 The ends of all tubes, suspension tubes and nipples shall 
be flared not less than 1/8 in. over the diameter of the tube hole 
on all water-tube boilers and superheaters, or they may be flared 
not less than 1/8 in., rolled and beaded, or flared, rolled and welded. 

252 The ends of all tubes, suspension tubes and nipples of 
water-tube boilers and superheaters shall project through the tube 
sheets or headers not less than % i^- ^^^ more than I/2 in. before 
flaring. 



■ so^^^ 



^--/.. -^ 



,,■"90'":^ 







Stroiqht Base 
Buifbn Head 



■1.0 -\-> 
Cone Head 




Pan Head 



Bu-tton W^ad 





-1.7 



— LO 



<=.-'-/.7S 



..^.L-..^ 



— 1.0 -rr 



Doubly Radius Button Head 



Steeple Head Coun+ersunk Head Flat HcQd 

Dimensions may be larger or 1/10 smaller than those shown. 
Fillets under heads may be used but are not required. 

Fig. 20 Acceptable Forms of Eivet Heads 



Riveting 

253 Drilling of Holes. All rivet holes and staybolt holes and 
holes in braces and lugs shall be drilled full size or they may be 
punched not to exceed 14 in. less than full diameter for material 
over 5/16 in. in thickness, and i/g in. less than full diameter for 
material not exceeding 5/16 in. in thickness, and then drilled or 
reamed to full diameter. Plates, butt straps, braces, heads and lugs 
shall be firmly bolted in position by tack bolts for drilling or 
reaming all rivet holes in boiler plates except those used for the 
tack bolts. 

254 After drilling or reaming rivet holes the plates and butt 
straps shall be separated, the burrs and chips removed, the plates 



72 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

and butt straps reassembled metal to metal with barrel pins fitting 
the holes, and with tack bolts. 

255 Bivets. Eivets shall be of sufficient length to completely 
fill the rivet holes and form heads at least equal in strength to the 
bodies of the rivets. Forms of rivet heads that will be acceptable 
are shown in Fig. 20. 

256 Kivets shall be machine driven wherever possible, with 
sufficient pressure to fill the rivet holes, and shall be allowed to cool 
and shrink under pressure. Barrel pins fitting the holes and tack 
bolts to hold the plates firmly together shall be used. A rivet shall 
be driven each side of each tack bolt before removing the tack bolt. 

Calking 

257 Calking. The calking edges of plates, butt straps and 
heads shall be beveled to an angle not sharper than 70 deg. to the 
plane of the plate, and as near thereto as practicable. Every portion 
of the sheared surfaces of the calking edges of plates, butt straps 
and heads shall be planed, milled or chipped to a depth of not less 
than % in. Calking shall be done with a round-nosed tool. 

Manholes 

258 Manholes and Handholes. An elliptical manhole opening 
shall be not less than 11 by 15 in., or 10 by 16 in. in size. A circular 
manhole opening shall be not less than 15 in. in diameter. A hand- 
hole opening in a boiler, the greatest dimension of which exceeds 
6 in., shall be reinforced in accordance with the rules for manholes. 

259 A manhole reinforcing ring when used, shall be of steel or 
wrought-iron, and shall be at least as thick as the shell plate. 

260 Manhole frames on shells or drums when used, shall have 
the proper curvature, and on boilers over 48 in. in diameter shall 
be riveted to the shell or drum with two rows of rivets, which may 
be pitched as shown in Fig. 21. The strength of manhole frames 
and reinforcing rings shall be at least equal to the tensile strength 
of the maximum amount of the shell plate removed by the opening 
and rivet holes for the reinforcement on any line parallel to the 



4 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 73 

longitudinal axis of the shell through the manhole, or other 
opetoingj. 

261 The strength of the rivets in shear on each side of a man- 
hole frame or reinforcing ring shall be at least equal to the tensile 
strength of the maximum amount of the shell plate removed by 
the opening and rivet holes for the reinforcement on any line 
parallel to the longitudinal axis of the shell, through the manhole, 
or other opening. 

262 Manhole plates shall be of wrought steel or shall be steel 
castings. 

■ {Longifudinal 

^ Center Line of Shell 




Pig. 21 Method op Riveting Manhole Frames to 
Shells or Drums with Two Eows of Rr^ets 

263 The minimum width of bearing surface, for a gasket on a 
manhole opening shall be % in. No gasket for use on a manhole or 
handhole of any boiler shall have a thickness greater than ^ in. 

264 All boilers must be provided with suitable manhole or 
handhole openings, except special types where they are manifestly 
not needed or used. A manhole shall be located in the front head, 
below the tubes, of a horizontal return tubular boiler 48 in. or over 
in diameter. Smaller boilers shall have either a manhole or a hand- 
hole below the tubes. There shall be a manhole in the upper part 
of the shell or head of a fire-tube boiler over 40 in. in diameter, 
except a vertical fire-tube boiler, or except on internally fired 
boilers not over 48 in. in diameter. The manhole may be placed in 
the head of the dome. Smaller boilers shall have either a manhole 
or a handhole abo^^e the tubes. 



74 report of boiler code committee, am.soc.m.e. 

Washout Holes 

265 A traction, portable or stationary boiler of the locomotive 
type shall have not less than six handholes, or washout plugs, 
located as follows : one in the rear head below the tubes ; one in the 
front head at or about the line of the crown sheet; four in the 
lower part of the waterleg ; also, where possible, one near the throat 
sheet. 

266 A vertical fire-tube boiler, except boilers of steam Sre- 
engines, or boilers 24 in. or less in diameter, shall have not less than 
seven handholes, located as follows : Three in the shell at or about 
the line of the crown sheet; one in the shell at or about the water 
line or opposite the fusible plug when used; three in the shell at 



TABLE 8 



minimum number of pipe threads for connections to 
boilers 



Size of pipe connec- 
tion, in 


1 and 1 % 


1 ^ and 2 


2y2 to 4 
inclusive 


4l^ to 6 
inclusive 


7 and 8 


9 and 10 


12 






Number of threads 
per inch 


llVz 


111/2 


8 


8 


8 


8 


8 


Minimum number of 
threads required in 
opening 


4 


5 


7 


8 


10 


12 


13 






Minimum thickness 
of material required 
to give above num- 
ber of threads, in. . 


0.348 


0.435 


0.875 


1 


1.25 


1.5 


1.625 



the lower part of the waterleg. A vertical fire-tube boiler, sub- 
merged-tube type, shall have two or more handholes in the shell, 
in line with the upper tube sheet. All boilers 24 in. or less in 
diameter shall have at least one opening for inspection and one 
opening in addition to the blow-off for washing out the boiler, these 
openings to be fitted with brass plugs. 

267 A vertical fire-tube boiler of a steam fire-engine sEall have 
at least three brass washout plugs of not less than 1-in. iron pipe 
size, screwed into the shell and located as follows : one at or about 
the line of the crown sheet ; two at the lower part of the waterleg. 

Threaded Openings 

268 Threaded Openings. A pipe connection 1 in. in diameter 
or over shall have not less than the n.umber of threads given in 
Table 8. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 75 

If the thickness of the material in the boiler is not sufficient to 
give such number of threads, the opening shall be reinforced by a 
pressed steel, cast steel, or bronze composition flange, or plate, so 
as to provide the required number of threads. 

When the maximum allowable working pressure exceeds 100 
lb. per sq. in., a connection riveted to the boiler to receive a flanged 
fitting shaU be used for all pipe openings over 3 in. pipe size. 

Safety Valves 

269 Safety Valve Requirements. Each boiler shall have two 
or more safety valves, except a boiler for which one safety valve 
having a relieving capacity of 2000 lb. per hour or less, is required 
by the rules.^ 

270 The safety valve capacity for each boiler shall be such that 
the safety valve or valves will discharge all the steam that can be 
generated by the boiler without allowing the pressure to rise more 
than 6 per cent above the maximum allowable working pressure, 
or more than 6 per cent above the highest pressure to which any 
valve is set. 

271 One or more safety valves on every boiler shall be set at or 
below the maximum allowable working pressure. The remaining 
valves may be set within a range of 3 per cent above the maxi- 
mum allowable working pressure, but the range of setting of all of 
the valves on a boiler shall not exceed 10 per cent of the highest 
pressure to which any valve is set. 

272 Safety valves shall be of such a type that no failure of 
any part can obstruct the free and full discharge of steam from the 
valve. Safety valves may be of the direct spring-loaded pop 
type with seat and bearing surface of the disk inclined at any 
angle between 45 deg. and 90 deg. to the center line of the spindle. 
The valve shall be rated at a pressure 3 per cent in excess of that 
at which the valve is set to blow. 

Safety valves may be used which give any opening up to the 
full discharge capacity of the area of the opening at the base of 
the valve, provided the movement of the valve is gradual so as not 
to induce lifting of the water in the boiler. 

All safety valves shall be so constructed that no detrimental 
shocks are produced through the operation of the valve. Weighted 
lever safety valves shall not be used. 

*The method of computing the relieving capacity of the safety valves shall be «^ 
given in Par. 421 of the Appendix. 



76 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

273 Each safety valve shall be plainly marked by the manu- 
facturer. The markings may be stamped on the body, cast on the 
body, or stamped or cast on a plate or plates permanently secured 
to the body, and shall contain the following: 

a The name or identifying trademark of the manufacturer 

b The nominal diameter 

c The steam pressure at which it is set to blow 

d Blow down, or difference between the opening and closing 

pressures 
e The weight of steam discharged in pounds per hour at a 

pressure 3 per cent higher than that for which the valve is 

set to blow 
/ A.S.M.E. Std. 

274 The total relieving capacity of the safety valve or valves 
required on a boiler shall be determined on the basis of 6 lb. of 
steam per hour per sq. ft. of boiler heating surface for water- 
tube boilers. For all other types of power boilers, the minimum 
allowable relieving capacity shall be determined on the basis of 
5 lb. of steam per hour per sq. ft. of boiler heating surface 
for boilers with maximum allowable working pressures above 100 
lb., and on the basis of 3 lb. of steam per hour per sq. ft. of 
boiler heating surface for boilers with maximum allowable working 
pressures at or below 100 lb. per sq. in. 

The heating surface shall be computed for that side of the 
boiler surface exposed to the products of combustion, exclusive of 
the superheating surface. In computing the heating surface for 
this purpose, only the tubes, fireboxes, shells, tube sheets and the 
projected area of headers need be considered. The minimum 
number and size of safety valves required shall be determined on 
the basis of the total relieving capacity and the relieving capacity 
marked on the valves by the manufacturer. 

275 Safety valve capacity may be checked in any one of the 
three following ways, and if found insufficient, additional capacity 
shall be provided : 

a By making an accumulation test ; that is, by shutting off 
all other steam discharge outlets from the boiler and 
forcing the fires to the maximum. The safety valve 
equipment shall be sufficient to prevent an excess pres- 
sure beyond that specified in Par. 270. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 77 

b By measuring the maximum amount of fuel that can be 
burned and computing the corresponding evaporative 
csLpacity upon the basis of the heating value of the fuel. 
See Appendix, Pars. 420 to 426. 

c By determining the maximum evaporative capacity by 
measuring the feed water. The sum of the safety valve 
capacities marked on the valves, shall be equal to or 
greater than the maximum evaporative capacity of the 
boiler. 

276 When two or more safety valves are used on a boiler, they 
may be either separate or twin valves made by mounting individual 
valves on Y-bases, or duplex, triplex or multiplex valves having two 
or more valves in the same body casing. 

277 The safety valve or valves shall be connected to the boiler 
independent of any other steam connection, and attached as close as 
possible to the boiler, without any unnecessary intervening pipe or 
fitting. Every safety valve shall be connected so as to stand in an 
upright position, with spindle vertical, when possible. 

278 Each safety valve shall have full-sized direct connection to 
the boiler. No valve of any description shall be placed between the 
safety valve and the boiler, nor on the discharge pipe between the 
safety valve and the atmosphere. When a discharge pipe is used, it 
shall be not less than the full size of the valve, and shall be fitted 
with an open drain to prevent water from lodging in the upper part 
of the safety valve or in the pipe. 

279 If a muffler is used on a safety valve it shall have sufficient 
outlet area to prevent back pressure from interfering with the proper 
operation and discharge capacity of the valve. The muffler plates 
or other devices shall be so constructed as to avoid any possibility 
of restriction of the steam passages due to deposit. When an elbow 
is placed on a safety valve discharge pipe, it shall be located close 
to the safety valve outlet or the pipe shall be securely anchored and 
supported. All safety valve discharges shall be so located or piped 
as to be carried clear from running boards or working platforms 
used in controlling the main stop valves of boilers or steam headers. 

Where discharge pipes are used, the cross-sectional area at any 
point shall be at least equal to the combmed areas of the discharge 
outlets of the valves discharging therethrough. Ample drainage 



78 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

shall be provided at or near each safety valve and where the water 
of condensation may collect. 

280 When a boiler is fitted with two or more safety valves on 
one connection, this connection to the boiler shall have a cross- 
sectional area not less than the combined area of all of the safety 
valves with which it connects. 

281 Safety valves shall operate without chattering and shall 
be set and adjusted as follows: To close after blowing down not 
more than 4 lb. on boilers carrying an allowed pressure less than 
100 lb. per sq. in. gage. To close after blowing down not more than 
6 lb. on boilers carrying pressures between 100 and 200 lb. per sq. 
in. gage inclusive. To close after blowing down not more than 8 
lb. on boilers carrying over 200 lb. per sq. in. gage. 

282 To insure the valve being free, each safety valve shall 
have a substantial lifting device by which the valve may be raised 
from its seat at least 1/16 in. when there is no pressure on the boiler „ 

283 The seats and disks of safety valves shall be of non-ferrous 
material. The seat of a safety valve shall be fastened to the body 
of the valve in such a way that there is no possibility of the seat 
lifting. 

284 Springs used in safety valves shall not show a permanent 
set exceeding 1/16 in. ten minutes after being released from a cold 
compression test closing the spring solid. The spring shall be so 
constructed that the valve can lift from its seat at least 1/10 the 
diameter of the seat before the coils are closed or before there is 
other interference. 

285 The spring in a safety valve shall not be used for any 
pressure more than 10 per cent above or below that for which it 
was designed. 

286 A safety valve over 3 in. size, used for pressures greater 
than 15 lb. per sq. in. gage, shall have a flanged inlet connection. 
The dimensions of flanges subjected to boiler pressure shall con- 
form to the American Standard given in Tables 16 and 17 of the 
Appendix for the pressures therein specified, except that the face 
of the safety valve flange and the nozzle to which it is attached 
may be flat and without the raised face for pressures up to and 
including 250 lb. per sq. in. For higher pressures, the raised face 
shall be used. 



NEW INSTALLATIONS, PART I, SECTION I, POWEii B0ILER3 79 

287 When the valve body is marked with the letters A.S.M.E. 
Std. as required by Par. 273, this shall be a guarantee by the 
manufacturer that the valve conforms to the details of construction 
herein specified. 

288 Every superheater shall have one or more safety valves 
near the outlet. The discharge capacity of the safety valve or 
valves on an attached superheater may be included in determining 
the number and size of the safety valves for the boiler, provided 
there are no intervening valves between the superheater safety 
valve and the boiler, and provided the discharge capacity of the 
safety valve or valves on the boiler, as distinct from the super- 
heater, is at least 75 per cent of the total valve capacity required. 

289 Every safety valve used on a superheater, discharging 
superheated steam, shall have a steel body with a flanged inlet con- 
nection, and shall have the seat and disk of nickel composition or 
equivalent material, and the spring fully exposed outside of the 
valve casing so that it shall be protected from contact with the 
escaping steam. 

290 Every boiler shall have proper outlet connections for the 
required safety valve or valves, independent of any other outside 
steam connection, the area of opening to be at least equal to the 
aggregate nominal area of all of the safety valves to be attached 
thereto. An internal collecting pipe, splash plate or pan may be 
used, provided the total area for inlet of steam thereto is not less 
than one and one-half times the aggregate area of the attached 
safety valves. The holes in such collecting pipes shall be at least 
34 in. in diameter and the least dimension in any other form of 
opening for inlet of steam shall be %. in. 

Water and Steam Gages 

291 Water Glasses and Gage Cocks. Each boiler shall have 
at least one water-gage glass, the lowest visible part of which shall 
be not less than 2 in. above the lowest permissible water level. The 
lowest permissible water level for various classes of boilers shall be 
the location for the fusible plug as given in Par. 430 of the 
Appendix. 

292 Automatic shut-off valves on water gages, if permitted 
to be used, shall conform to the requirements given in Par. 427 of 
the Appendix. 



80 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

293 When sliiit-offs are used on the connections to a water 
column, they shall be either outside screw and yoke type gate valves 
or stop cocks with levers permanently fastened thereto, and such 
valves or cocks shall be locked or sealed open. 

294 Each boiler shall have three or more gage cocks, located 
within the range of the visible length of the water glass, except when 
such boiler has two water glasses with independent connections to 
the boiler and located on the same horizontal line and not less than 
2 ft. apart. 

295 No outlet connections, except for damper regulator, feed- 
water regulator, drains or steam gages, shall be placed on the pipes 
connecting a water column to a boiler. 

296 Steam Gages. Each boiler shall have a steam gage con- 
nected to the steam space or to the water column or its steam con- 
nection. The steam gage shall be connected to a siphon or equiva- 
lent device of sufficient capacity to keep the gage tube filled with 
water and so arranged that the gage cannot be shut off from the 
boiler except by a cock placed near the gage and provided with a 
tee or lever handle arranged to be parallel to the pipe in which it 
is located when the cock is open. Connections to gages shall be of 
brass, copper or bronze composition. 

Where the use of a long pipe becomes necessary, an exception 
may be made to the rule that the gage must be arranged so that it 
cannot be shut off except by a cock placed near the gage and a 
shut-off valve or cock arranged so that it can be locked or sealed 
open may be used near the boiler. Such a pipe shall be of ample 
size and arranged so that it may be cleared by blowing out. 

297 The dial of the steam gage shall be graduated to not less 
than 1% times the maximum allowable working pressure on the 
boiler. 

298 Each boiler shall be provided with a ^,4-in. pipe size valved 
connection for the exclusive purpose of attaching a test gage when 
the boiler is in service, so that the accuracy of the boiler steam gage 
can be ascertained. 

Fittings and Appliances 

299 Nozzles and Fittings. Flanged cast iron pipe fittings used 
for boiler parts, for pressures up to and including 160 lb. per sq. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 81 

in., shall conform to the American Standard given in Tables 16 
and 17 of the Appendix, except that the face of the flange of a 
safety valve as well as that of a safety valve nozzle, may be flat and 
without the raised face. 

See Par. 12 for exceptions. For pressures above 160 lb. per sq. 
in., cast iron shall not be used for boiler pressure parts except for 
fittings under 2 in. pipe size or equivalent cross-sectional area. See 
Pars. 9 and 245. 

An allowable variation of 20 per cent from the flange thickness 
required by Tables 16 and 17 may be made for steel cast and 
forged steel fittings, leaving the drilling of bolt holes unchanged. 
For pressures above 250 lb. per sq. in., the flange thickness and the 
thickness of the bodies shall be increased to keep within the same 
deflection limits and to give at least the same factor of safety as 
the fittings specified in Tables 16 and 17. The flange of a safety 
valve may have a flat face for pressures up to and including 250 
lb. per sq. in., and shall have a raised face at higher pressures ; a 
safety valve nozzle may have a flat face for pressures up to and 
including 250 lb. per sq. in. and shall have a raised face at higher 
pressures. Tables 16 and 17 do not apply to flanges on the boiler 
side of steam nozzles or to flanges left by the manufacturer as part 
of the boiler, and do not apply to fittings designed as part of the 
boiler, 

300 The minimum number of threads that a pipe or fitting 
shall screw into a tapped hole shall correspond to the numerical 
values given for number of threads in Table 8 (page 74). 

301 Stop Valves. Each steam-discharge outlet over 2 in. in 
diameter, except safety valve and superheater connections, shall be 
fitted with a stop valve or valves of the outside-screw and yoke 
type, located as near the boiler as practicable. 

302 The main stop valves of boilers shall be extra heavy when 
the maximum allowable working pressure exceeds 125 lb. per sq. in. 
The fittings between the boiler and such valve or valves shall be 
extra heavy, as specified in Table 17 of the Appendix. 

303 When two or more boilers are connected to a common 
steam main, two stop valves, with an ample free-blow drain between 
them, shall be placed in the steam connection between each boiler 
and the steam main. The discharge of this drain valve must be 
visible to the operator while manipulating the valve. The stop 
valves shall consist preferably of one automatic non-return valve 



82- 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



(set next the boiler) and a second valve of the outside-screw and 
yoke type ; or, two valves of the outside screw and yoke type may 
be used. 

304 When a stop valve is so located that water can accumulate, 
ample drains shall be provided. 

305 Steam Mains. Provisions shall be made for the expansion 
and contraction of steam mains connected to boilers, by providing 
substantial anchorage at suitable points, so that there shall be no 
undue strain transmitted to the boiler. Steam reservoirs shall be 
used on steam mains when heavy pulsations of the steam currents 
cause vibration of the boiler shell plates. 




Fig. 22 Typical Boiler Bushings and Flange 



. 306 Each superheater shall be fitted with a drain. 

307 Blow-off Piping. A surface blow-off shall not exceed 1^ 
in. pipe size and the internal and external pipes, when used, shall 
form a continuous passage, but with clearance between their ends 
and arranged so that the removal of either will not disturb the 
other. A properly designed brass or steel bushing as shown in 
Fig. 22, or a flanged connection, shall be used. 

308 Each boiler shall have a bottom blow-off pipe, fitted with 
a valve or cock, in direct connection with the lowest water space 
practicable ; the minimum size of pipe and fittings shall be 1 in. and 
the maximum size shall be 2i/2 in. Globe valves shall not be used 
on such connections. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 83 

309 A bottom blow-off cock shall have the plug held in place by 
a guard or gland. The end of the plug shall be distinctly marked 
in line with the passage. 

310 The blow-off pipe or pipes shall be extra heavy from boiler 
to valve or valves, and shall run full size without reducers or bush- 
ings. All fittings between the boiler and valves shall be of steel. 

311 a On all boilers except those used for traction and portable 
purposes, when the maximum allowable working pressure exceeds 
125 lb. per sq. in., each bottom blow-off pipe shall have two valves, 
or a valve and a cock, and such valves, or valve and cock, shall be 
extra heavy, except that on a boiler having multiple blow-off pipes, 
a single master valve may be placed on the common blow-off pipe 
from the boiler, in which case only one valve on each individual 
blow-off is required. 

h Every traction and portable boiler shall have a bottom blow- 
off valve; when the maximum allowable working pressure exceeds 
125 lb. per sq. in., the blow-off valve shall be extra heavy. 

312 A bottom blow-off pipe when exposed to direct furnace heat 
shall be protected by fire-brick, a substantial cast-iron removable 
sleeve or a covering of non-conducting material. 

313 An opening in the boiler setting for a blow-off pipe shall 
be arranged to provide for free expansion and contraction. 

314 Feed Piping. The feed pipe of a boiler shall have an 
open end or ends inside of the boiler. 

315 The feedwater shall discharge at about three-fifths the 
length of a horizontal return tubular boiler from the front head (ex- 
cept a horizontal return tubular boiler equipped with an auxiliary 
feedwater heating and circulating device), above the central rows 
of tubes, when the diameter of the boiler exceeds 36 in. The feed 
pipe shall be carried through the head or shell near the front end 
in the manner specified for a surface blow-off in Par. 307, and be 
securely fastened inside the shell above the tubes. 

In Fig. 22 is illustrated a typical form of flange for use on 
boiler shells for passing through piping such as feed, surface, 
blow-off connections, etc., and which permits of the pipes being 
screwed in solid from both sides in addition to the reinforcing of 
the opening in the shell. 

In other types of boilers where both internal and external pipes 
making a continuous passage are employed, the boiler bushing of 
its equivalent shall be used. 



«4 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

316 Feedwater shall not discharge in a boiler close to riveted 
joints in the shell or to furnace sheets. 

317 The feed pipe shall be provided with a check valve near 
the boiler and a valve or cock between the check valve and the boiler, 
and when two or more boilers are fed from a common source, there 
shall also be a globe valve on the branch to each boiler, between the 
check valve and the source of supply. Wherever globe valves are 
used on feed piping, the inlet shall be under the disk of the valve. 

318 When a pump, inspirator or injector is required to supply 
feedwater to a boiler plant of over 50 h. p., more than one such 
appliance shall be provided. 

319 LampJirey Fronts. Each boiler Stted with a Lamphrey 
boiler-furnace mouth protector, or similar appliance, having valves 
on the pipes connecting them to the boiler, shall have these valves 
locked or sealed open. Such valves when used, shall be of the 
straightway type. 

320 Water Column Pipes. The minimum size of pipes connect- 
ing the water column to a boiler shall be 1 in. Water-glass fittings 
or gage cocks may be connected direct to the boiler. 

321 The water connections to the water column of a boiler shall 
be of brass and shall be provided with a cross to facilitate cleaning. 
Either the water column or this connection shall be fitted with a 
drain cock or drain valve with a suitable connection to the ashpit, or 
other safe point of waste. The water-column blow-off pipe shall be 
at least % in. 

322 The steam connection to the water column of a horizontal 
return tubular boiler shall be taken from the top of the shell or the; 
upper part of the head ; the water connection shall be taken from a 
point not less than 6 in. below the center line of the shell. 

Setting 

323 Methods of Support. A horizontal return tubular boiler 
over 78-in. in diameter shall be supported from steel lugs by the out- 
side suspension type of setting, independent of the boiler side walls. 
The lugs shall be so designed that the load is properly distributed 

■ between the rivets attaching them to the shell and so that no more 
than tv/o of these rivets come in the same longitudinal line on each 
lug. The distance girthwise of the boiler from the centers of the 
bottom rivets to the centers of the top rivets attaching the lugs shall 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 85 

be not less than 12 in. The other rivets used shall be spaced evenly 
between these points. If more than four lugs are used they shall be 
set in four pairs. 

324 A horizontal return tubular boiler over 54 in., and up to 
and including 78 ia. in diameter, shall be supported by the outside 
suspension type of setting, or at four points by not less than eight 
steel or cast-iron brackets set in pairs. A horizontal return tubular 
boiler up to and including 54 in. in diameter shall be supported by 
the outside suspension type of setting, or by not less than two steel 
or east-iron brackets on each side. 

325 Lugs or brackets, when used to support a boiler of any 
type, shall be properly fitted to the surfaces to which they are at- 
tached. The shearing and crushing stresses on the rivets used for 
attaching the lugs or brackets shall not exceed 8 per cent of the 
strength given in Pars. 15 and 16. For traction or portable boilers, 
studs with pipe threads may be used. 

326 Wet-bottom stationary boilers shall have a space of not 
less than 12 in. between the bottom of the boiler and the floor line, 
with access for inspection. 

327 Access and Firing Doors, The minimum size of an access 
door to be placed in a boiler setting shall be 12 by 16 in. or equiva- 
lent, area, 11 in. to be the least dimension in any case. 

328 A water-tube boiler shall have the firing doors, furnace 
inspection doors and clinker doors of the inward-opening type, 
unless such doors are provided with substantial and effective latch- 
ing or fastening devices to prevent them from being blown open by 
pressure on the furnace side. 

Hydrostatic Tests 

329 Hydrostatic Pressure Tests. After a boiler has been com- 
pleted, it shall be subjected to a hydrostatic test of one and one-half 
times the maximum allowable working pressure. The pressure shall 
be under proper control so that in no case shall the required test 
pressure be exceeded by more than 6 per cent. 

330 During a hydrostatic test, the safety valve or valves shall 
be removed or each valve disk shall be held to its seat by means of 
a testing clamp and not by screwing down the compression screw 
upon the spring. 



'&6 eeport of boiler code committee, am.soc.m.e. 

Stamping 

331 Stamping of Boilers. In laying out shell plates, furnace 
sheets and heads in the boiler shop, care shall be taken to leave at 
least one of the stamps, specified in Par. 36 of these Rules, so located 
as to be plainly visible when the boiler is completed ; except that the 
tube sheets of a vertical fire-tube boiler and butt straps shall have 
at least a portion of such stamps visible sufficient for identification 
when the boiler is completed. 

332 Each boiler shall conform in every detail to these Eules, 
and shall be distinctly stamped with the symbol as shown in Fig. 
23, denoting that the boiler was constructed in accordance therewith. 

After obtaining the stamp to be used when boilers are to be 
constructed to conform with the A.S.M.E. Boiler Code, a state in- 
spector, municipal inspector, or an inspector employed regularly 
by an insurance company which is authorized to do a boiler in- 
surance business in the state in which the boiler is built and in 
the state in which it is to be used, if known, is to be notified that 
an inspection is to be made and he shall inspect such boilers during 
construction and after completion. At least two inspections shall 
be made, one before reaming rivet holes and one at the hydrostatic 
test. In stamping the boiler after completion, if built in compliance 
with the Code, the builder shall stamp the boiler in the presence 
of the inspector, after the hydrostatic test, with the A.S.M.E, Code 
stamp, the builder's name and the serial number of the manu- 
facturer. A data sheet shall be filled out and signed by the manu- 
facturer and the inspector. This data sheet together with the stamp 
on the boiler shall denote that it was constructed in accordance 
with the A.S.M.E. Boiler Code. 

Each boiler shall be stamped adjacent to the symbol as shown 
in Fig. 24, with the following items with intervals of about one-half 
inch between the lines: 

1. Manufacturer's serial number 

2. State in which boiler is to be used 

3. Manufacturer's State standard number 

4. Name of manufacturer 

5. State's number 

6. Year put in service 

7. Maximum working pressure when built 

Items 1, 2, 3, 4 and 7 are to be stamped at the shop where built. 
Items 5 and 6 are to be stamped by the proper authority at point of 
installation. 



NEW INSTALLATIONS, PART I, SECTION I, POWER BOILERS 87 

J A sample data sheet appears in the Appendix, after page 128.) 

Stamps for the official symbol shown in Fig. 23 are obtainable 
from The American Society of Mechanical Engineers. 




Fig. 23 Official Symbol for Stamp to Denote The American 
Society of Mechanical Engineers Uniform Standard . 



® 




(State in which boiler is to be used) 


(Manufacturer's State standard number) 


(Name of manufacturer) 


(State's number) (Year put in service) 


j Manufacturer's ) 
1 Serial number j" 


(Maximum working pressure when built) 



Fig. 24 Form of Stamping 



333 Location of Stamps. The location of stamps shall be as 
follows : 

a On horizontal return tubular boilers— on the front head, 
above the central rows of tubes. 

h On horizontal flue boilers— on the front head, above the 
flues. 

C On traction, portable or stationary boilers of the locomo- 
tive type or Star water-tube boilers— on the furnace end, 
above the handhole. 

d On vertical fire tube and vertical submerged tube boilers— 
on the shell above the fire door. 

e On water-tube boilers, Babcock & Wilcox, Stirling, Heine 
and Robb-Mumford standard types— on a head above 



88 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

the manhole opening, preferably on the flanging of the 

manhole opening. 
/ On vertical boilers, Climax or Hazleton type— on the top 

head. 
g On Cahall or Wickes vertical water tube boilers— on the 

upper drum, above the manhole opening. 
h On Scotch marine boilers— on the front head, above the 

center or right-hand furnace. 
i On Economic boilers— on the front head, above the central 

row of tubes. 
3 On any of the above types where there is not sufficient 

space in the place designated, and for other types and 

new designs— in a conspicuous place. 

334 The American Society of Mechanical Engineers' standard 
stamp and the boiler builder 's stamps shall not be covered by insulat- 
ing or other material. 



A.S.M.E. BOILER CODE 



PART I— SECTION II 

BOILERS USED EXCLUSIVELY FOR LOW PRESSURE 

STEAM AND FOR HOT WATER HEATING AND 

HOT WATER SUPPLY 

(this does not apply to economizers or feed water heaters) 

General 

335 The Rules for power boilers shall apply : 

a To all steel plate hot-water boilers over 60 in. in diameter. 

h To all steel plate hot-water boilers where the grate area ex- 
ceeds 10 sq. ft. and the maximum allowable workings 
pressure exceeds 50 lb. per sq. in. 

c Under other conditions, the following rules shall apply. 

Materials 

336 Specifications are given in these Rules, Pars. 23 to 178, for 
the important materials used in the construction of boilers, and 
where given, the materials shall conform thereto. 

337 Flange steel may be used entirely for the construction of 
steam heating boilers covered in this section, but in no case shall 
steel of less than % in. in thickness, nor tube sheets or heads of less 
than 5/16 in. in thickness be used. 

Maximum Allowable Working Pressure 

338 The maximum allowable working pressure shall not exceed 
15 lb. per sq. in. on a boiler built under these Rules to be used 
exclusively for low-pressure steam heating. 

The maximum allowable working pressure for a hot-water boiler 
or heater used or a closed system shall be one-half of the maximum 
allowable working pressure for the same hot-water boiler or heater 
when used on an open system. 

Hot-water systems shall be designated as either open or closed 
systems. Open systems are those in which the pressure is balanced 
by a fluid column, the cross sectional area of which is at least equal 
to the cross sectional area of the water supply pipe, or where the 

89 



90 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

system is freely connected to the street supply. All other systems 
are classed as closed systems. 

Open systems shall be so installed that there will be no oppor- 
tunity for the fluid column to freeze or to be accidentally shut off. 
If a valve is used in the supply line, it shall be locked and sealed 
open and bear a tag stating that the system shall be relieved of 
pressure whenever the valve is closed. 

339 A boiler to be used exclusively for low-pressure steam 
heating may be constructed either of cast-iron, steel cast, or wrought 
iron or steel, or any combination of these, but in all cases the con- 
necting rods and bolts shall be wrought iron or steel. 

340 All steel-plate hot-water diudi' steam-heating boilers shall 
have a factor of safety of not less than 5. 

Boiler Joints 

341 Longitudinal lap joints will be allowed on boilers to be 
used exclusively for low-pressure steam heating, when the maximum 
allowable working pressure does not exceed 15 lb. per sq. in., and 
the diameter of the boiler shell does not exceed 60 in. 

342 The longitudinal joints of a horizontal return-tubular 
boiler if of the lap type, shall be not over 12 ft. in length. 

343 In a hot-water boiler to be used exclusively for heating 
buildings or hot-water supply, when the diameter does not exceed 
60 in. and the grate area does not exceed 10 sq. ft., or equivalent 
as defined in Pars. 359 and 360, longitudinal lap joints will be 
allowed. "When the grate area exceeds 10 sq. ft., or equivalent as 
defined in Pars. 359 and 360, and the diameter of the boiler does 
not exceed 60 in., longitudinal lap joints will be allowed provided 
the maximum allowable working pressure does not exceed 50 lb. 
per sq, in. 

344 Protection of Joints. "When a boiler is built wholly or 
partially of steel and is used exclusively for low-pressure steam 
heating, or when a hot-water boiler is used exclusively for heating 
buildings or for hot-water supply, it shall not be necessary to water 
jacket the rivets in the fire-box where one end of each rivet is 
exposed to the fire or direct radiant heat from the fire, provided 
any one of the following conditions is fulfilled: 

a Where the ends of the rivets away from the fire are protected by 
means of natural drafts of cold air induced in the regular 
operation of the boiler : 

h Where the ends of the rivets away from the fire are in the open air ; 

c Where the rivets are protected by the usual charges of fresh fuel, 
which is not burned in contact with the rivets. 



new installations, part i, section ii, heating boilers 91 

Washout Holes 

345 A boiler used for low-pressure steam or hot-water heating 
or for hot-water supply shall be provided with washout holes to 
permit the removal of any sediment that may accumulate therein. 
Steel shell boilers of the locomotive or vertical fire-tube type shall 
conform to the requirements of Pars. 265 and 266 for washout holes. 

Boiler Openings 

346 Flanged Connections. Openings in boilers having flanged 
connections shall have the flanges conform to the American Standard 
given in Tables 16 or 17 of the Appendix, for the corresponding 
pipe size, and shall have the corresponding drilling for bolts or studs. 

Safety Valves 

347 Outlet Connections for Safety and Water Relief Valves. 
Every boiler shall have proper outlet connections for the required 
safety, or water-relief valve or valves, independent of any other con- 
nection outside of the boiler, the area of the opening to be at least 
equal to the aggregate area of all of the safety valves with which 
it connects. A screwed connection may be used for attaching a 
safety valve to a heating boiler. This rule applies to all sizes of 
safety valves. 

348 Safety Valves. Each steam boiler shall be provided with 
one or more safety valves of the spring-pop type which cannot be 
adjusted to a higher pressure than 15 lb. per sq. in. 

349 Water Relief Valves. Water relief valves shall be placed 
on all hot-water heating and supply systems and be connected to 
the boiler or heater. The valve shall be of the diaphragm-operating 
type set to open at or below the maximum allowable working pres- 
sure, the diaphragm being so designed that, if the valve fails to 
open, the diaphragm will rupture at a pressure not exceeding 50 
per cent above the maximum allowable working pressure. 

350 The outlets of water relief valves shall have open discharges 
in plain sight. 

351 No safety valve for a steam' boiler shall be smaller than 
1 in. nor greater than 4)^ in. standard pipe size. No water relief 
valve shall be smaller than ^ in. nor greater than 2 in. standard 
pipe size. 

352 When two or more safety or water relief valves are used 
on a boiler or heating system, they may be single, twin or duplex 
valves. 



92 



KEPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



353 Safety or water-relief valves shall be connected to the 
boilers or heating systems independent of other connections and be 
attached directly, or as close as possible, to the boiler or heater 
without any intervening pipe or fittings, except the Y-base forming 
a part of the twin valve or the shortest possible connection. A 
safety valve or water-relief valve shall not be connected to an 
internal pipe in the boiler or heater. Safety valves shall be con- 
nected so as to stand upright with the spindle vertical when 
possible. 

TABLE 9 ALLOWABLE SIZES OF SAFETY [VALVES FOR STEAM HEATING 

BOILERS 
(Maximum Allowable Working Pressure, 15 lb. per sq. in.) 



Water Evaporated 










per Sq. Ft. of 










Grate Surface per 


50 


75 


100 


125 


Hr., Lb. 










Diameter 


Area 










of Valve 


of Valve 




Area of Grate, Sq. Ft. 




in. 


Sq. In. 




k. 






1 


0.7854 


2.25 


1.50 


1.00 


1.00 


1% 


1.2272 


3.50 


2.25 


1.75 


1.50 


1% 


1.7671 


5.00 


3.25 


2.50 


2.00 


2 


3.1416 


8.75 


6.00 


4.25 


3.50 


21/2 


4.9087 


13.75 


9.25 


7.00 


5.50 


3 


7.0686 


20.00 


13.25 


10.00 


8.00 


3V. 


9.6211 


27.25 


18.00 


13.50 


10.75 


4 


12,5660 


35.50 


23.50 


17.75 


14.25 


4% 


15.9040 


44.75 


30.00 


22.50 


18.00 



TABLE 9a ALLOWABLE SIZES OF WATER RELIEF VALVES FOR WATER 
HEATING BOILERS AND FOR HOT WATER SUPPLY B-OILERS 



Diameter of Valve, In. 


Area of Grate, Sq. Ft. 


1 

1^ 

2 


Not exceeding 8 
Over 8 and not exceeding 13 
Over 13 and not exceeding 18 
Over 18 and not exceeding 28 



Above 28 sq. ft. of grate area, more than one valve shall be used, the sum of the 
areas handled by the valves as given in the Table to be equal to or greater than the 
grate area. 

354 No shut-off of any description shall be placed between the 
safety or water-relief valves and boilers or heaters, nor on discharge 
pipes between such valves and the atmosphere. 

355 When a discharge pipe is used its area shall be not less 
than the area of the valve or aggregate area of the valves with which 
it connects, and the discharge pipe shall be fitted with an open drain 
to prevent water from lodging in the upper part of the valve or in 
the pipe. When an elbow is placed on a safety or water relief valve 
discharge pipe, it shall be located close to the valve outlet or the 
pipe shall be securely anchored and supported. The safety or 



NEW INSTALLATIONS, PART I, SECTION II, HEATING BOILERS 93 

water-relief valves shall be so located and piped that there will be 
no danger of scalding attendants. 

356 Each safety valve used on a steam heating boiler shall 
have a substantial lifting device by which the valve may be raised 
from its seat at least 1/16 in. when there is no pressure on the boiler. 
A relief valve used on a hot-water heating system need not have a 
lifting device. 

357 Every safety valve or water-relief valve shall have plainly 
stamped on the body or cast thereon the manufacturer's name or 
trade mark and the pressure at which it is set to blow. The seats 
and discs of safety or water-relief valves shall be made of non- 
ferrous material. 

358 The minimum size of safety or water-relief valve or valves 
for each boiler or heater shall be governed by the grate area as 
shown by Table 9 or 9a. The equivalent grate area for oil or gas 
fired boilers or water heaters heated by steam shall be used as 
specified under Par. 360. 

When the conditions exceed those on which Table 9 is based, the 
following formula for bevel and flat seated valves shall be used : 

in which 

A =: area of direct spring-loaded safety valve per square 

foot of grate surface, sq. in. 
W =^ weight of water evaporated per square foot of grate 

surface per hour, lb. 
P=r pressure (absolute) at which the safety valve is set to 

blow, lb. per sq. in. 

Grate Area 

359 Douhle-Grate Dowtv-Draft Boilers. In boilers of this type 
the grate area shall be taken as the area of the lower grate plus 
one-quarter of the area of the upper grate. 

360 Boilers or Heaters Fired With Oil or Gas or Heated With 
Steam, In determining the number and size of safety or water- 
relief valve or valves:, for a boiler using gas or liquid fuel, 15 sq. ft. 
of heating surface shall be equivalent to one square foot of grate 
area. If the size of grate for use of coal is evident from the boiler 
design, such size may be the basis for the determination of the 
safety-valve capacity. 

For a heater heated with steam the maximum amount of steam 
that can be condensed per hour shall be determined and the equiva- 



94 REPORT CF BOILER CODE COMMITTEE, AM.SOC.M.E. 

lent grate surface taken as the maximum weight of steam con- 
densed in pounds per hour divided by 50 

Steam and Water Gages 

361 Steam Gages. Each steam boiler shall have a steam gage 
connected to the steam space or to the water column, or its steam 
connection, by means of a syphon or equivalent device of sufficient 
capacity to keep the gage tube filled with water and so arranged 
that the gage cannot be shut off from the boiler except by a cock 
placed near the gage and provided with a tee or lever handle 
arranged to be parallel with the pipe in which it is located when 
the cock is open. Pipe connections to steam gages less than 1 in. 
pipe size, shall be of brass, copper or bronze composition when the 
distance between the gage and point of attachment of pipe is over 
5 ft. If less than 5 ft., the connections shall be of brass, copper or 
bronze composition if less than ^ in. pipe size. The dial of a 
steam gage for a steam, heating boiler shall be graduated to not less 
than 30 lb. 

362 Pressure or Altitude Gages, Each hot-water boiler or 
heater shall have a gage connected in such a manner that it cannot 
be shut off from the boiler or heater except by a cock with tee or 
lever handle, placed on the pipe near the gage. The handle of the 
cock shall be parallel to the pipe in which it is located when the 
cock is open. Pipe connections to gages less than 1 in. pipe size, 
shall be made of brass, copper or bronze composition when the dis- 
tance between the gage and point of attachment of pipe is over 
5 ft. If loss than 5 ft., the connections shall be of brass, copper 
or bronze composition if less than y^ in. pipe size. The dial of the 
pressure or altitude gage shall be graduated to not less, than IJ/2 
times the maximum allowable working pressure. 

363 Thermometers. Each hot-water boiler or heater shall have 
a thermometer so located and connected that it shall be easily read- 
able when observing the water pressure or altitude. The thermom- 
eter shall be so located that it shall at all times indicate the tem- 
perature in degrees fahrenheit of the water in the boiler or heater. 

Temperature Regulators. A temperature regulator which will 
operate to prevent the temperature of the water from rising above 
200 deg. fahr. shall be used on all hot-water supply and hot-water 
heating systems in which the working pressure exceeds 30 lb. per 
sq. in. It shall also be used on all closed systems irrespective of 
the working pressure. 



new installations, part i, section ii, heating boilers 95 

Fittings and Appliances 
o64 Bottom Bloiv-off Pipes. Each boiler or heater shall have 
a blow-off pipe, fitted with a valve or cock, in direct connection 
with the lowest water space practicable. 

365 Damper Regulators. When a pressure damper re^alator 
is used, it shall be connected to the steam space of the boiler. 

366 Water Glasses. Each steam boiler shall have one or more 
water glasses. 

367 Gage Cocks. Each steam boiler shall have two or more gage 
cocks located within the range of the visible length of the water 
glass. 

368 Water Column Pipes. The minimum size of pipes connect- 
ing the water column of a boiler shall be 1 in. Water-glass fittings 
or gage cocks may be connected direct to the boiler. The steam 
connection to the water column of a horizontal return tubular boiler 
shall be taken from the top of shell or the upper part of the head ; 
the water connection shall be taken from a point not less than 6 in. 
below the center line of the shell. No connections, except for damper 
regulator, drains or steam gages,, shall be placed on the pipes con- 
necting a water column to a boiler. 

Methods of Setting 

369 Wet-bottom steel-plate boilers shall have a space of not less 
than 12 in. between the bottom of the boiler and the floor line with 
access for inspection. 

370 Access Doors. The minimum size of access door used in 
boiler settings shall be 12 by 16 in. or equivalent area, the least 
dimension being 11 in. 

371 The longitudinal joints of a horizontal return-tubular 
boiler shall be located above the fire-line. 

Hydrostatic Tests 

372 A shop test of 60 lb. per sq. in. hydrostatic pressure shall 
be applied to steel or cast-iron boilers or to the sections of cast-iron 
boilers which are used exclusively for low-pressure steam heating. 

373 Hot-water boilers for a maximum allowable working pres- 
sure not exceeding 30 lb. per sq. in. used exclusively for heating 
buildings or for hot-water supply, when constructed of cast-iron, 
steel cast, or wrought iron or plate steel or any combination of these, 
shall be subjected to a shop test of 60 lb. per sq. in. hydrostatic 
pressure applied to the boiler or, at the option of the manufacturer, 
to the sections thereof. 



96 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

374 A maximum allowable working pressure in excess of 30 lb. 
per sq. in,, but not exceeding 160 lb. per sq. in., will be allowed on 
hot-water boilers or heaters constructed of east iron, or of cast iron 
excepting the coL\necting nipples and bolts, used exclusively for 
heating buildings, or for hot- water supply, provided they are sub- 
jected as a whole or, at the manufacturer's option, in sections, to 
a shop hydrostatic test of 2^ times the maximum allowable work- 
ing pressure for an open system and 5 times the maximum allowable 
working pressure for a closed system. 

All hot-water boilers or heaters that are to be used for a working 
pressure in excess of 50 lb. per sq. in. on open systems, or for a 
working pressure in excess of 25 lb. per sq. in. on closed systems, 
are to be subjected to a field hydrostatic test upon the boiler after 
it is installed. The boiler isi not to be tested at a pressure in excess 
of the shop test required to be made by the manufacturer. For 
hot-water boilers or heaters constructed of cast-iron, or of cast iron 
excepting the connecting nipples and bolts, used exclusively for 
heating buildings or for hot-water supply, the hydrostatic pressure 
for the field test shall be 2)4 times the maximum allowable working 
pressure for open systems and 5 times the maximum allowable 
working pressure for closed systems. For steel plate boilers or 
heaters, the hydrostatic test pressure shall be 1^ times the maxi- 
mum allowable working pressure for open systems and 3 times the 
maximum allowable working pressure for closed systems. 

375 Individual shop inspection shall be required only for boilers 
which come under the rules for power boilers. 

Stamping 

376 Each plate of a completed boiler shall show a sufficient 
portion of the plate maker's stamp for identification. 

377 Name. All boilers referred to in this section shall be 
plainly and permanently marked with the manufacturer's name 
and the maximum allowable working pressure, this to be indicated 
in Arabic numerals, followed by the letters ^^Lb." 

All hot-water boilers or heaters are to bear a manufacturer's 
label, that is irremovably attached to the front section, stating the 
maximum allowable working pressure for which the boiler is allowed 
to be used on *'open systems'' and on ''closed systems." 

All heating boilers built according to these rules should be 
marked A.S.M.E. standard. 



A.S.M.E. BOILER CODE 



APPENDIX 



Efficiency of Joints 

410 Efficiency of Riveted Joints. The ratio which the strength 

of a "unit length of a riveted joint has to the same unit length of 

the solid plate is known as the efficiency of the joint and shall be 

calculated by the general method illustrated in the following examples : 

TS = tensile strength stamped on plate, lb. per sq. in. 

t = thickness of plate, in. 
• 5 := thickness of butt strap, in. 
P = pitch of rivets, in., on row having greatest pitch 
d = diameter of rivet after driving, in. = diameter of rivet: 
hole 




Fig. 25 Example of Lap Joint, Longitudinal 
OR Circumferential, Single-Riveted 



a = cross-sectional area of rivet after driving, sq. in. 

s = shearing strength of rivet in single shear, lb. per sq. in., 

as given in Par. 16 
S = shearing strength of rivet in double shear, lb. per sq. in., 

as given in Par. 16 
c = crushing strength of mild steel, lb. per sq. in., as given 

in Par. 15 
n = number of rivets in single shear in a unit length of joint 
N = number of rivets in double shear in a unit length of joint 

97 



98 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



411 Example: Lap joint, longitudinal or circumferential, single- 
riveted. 

A = strength of solid plate = PXtXTS 

B = strength of plate beween rivet holes = (P — d)t X TS 

C= shearing strength of one rivet in single shear =nXsX<x 

D = crushing strength of plate in front of one livet =dXtXc 

Divide B, C OT D (whichever is the least) by A, and the quotient will be the 

efficiency of a single-riveted lap joint as shown in Fig. 25. 



TAS=55,0001b. persg. in. 
i = Min.=0.25in. 
P = l^m. = 1.625 in. 
cZ=ii in. =0.6875 in. 
0=0.3712 sq. in. 
5 = 44,000 lb. per sq. in. 



c=95,0001b. persq. in. 
^ =1.625X0.25X55,000=22,343 
B = (l .625—0.6875) 0.25 X55,000 = 12,890 
C = 1 X44,000 X0.3712 = 16,332 
i) =0.6875X0.25X95,000 = 16,328 




Fig. 26 Example of Lap Joint, Longitudinal 
or circumfeeential, double-elveted 



12,890 jB) 
22,343 (A) 



=0.576= efficiency of joint 



412 Example: Lap joint, longitudinal or circumferential, double- 
riveted. 

A = strength of solid plate = PXtXTS 

B = strength of plate between rivet holes = (P — d) tXTS 

C= shearing strength of two rivets in single shear =nXsXa 

D = crushing strength of plate in front of two rivets =nXc?X<Xc 

Divide B, C ov D (whichever is the least) by A, and the quotient will be the 

efficiency of a double-riveted lap joint, as shown in Fig. 26. 



T/S=55,0001b.persq. in. 
i = ^ in. =0.3125 in. 
P=2J^in.=2.875in. 
d = % in. =0.75 in. 
a =0.4418 sq. in. 
fi= 44,000 lb. per sq. in. 



36,523 (B) 
49,414 iA) 



c =95,000 lb. per sq. in. 
^=2.875X0.3125X55,000 = 49,414 
^ = (2.875—0.75)0.3125X55,000=36,523 
0=2X44,000X0.4418=38,878 
D=2X0.75X0.3125X95,000=44,531 



=0.739 = efficiency of joint 



APPENDIX 99 

'413 Example: Butt and double strap joint, double-riveted. 

A = strength of solid plate =PXtXTS 

B = strength of plate between rivet holes in the outer row = (P — d) t X TS 

(7= shearing strength of two rivets in double shear, plus the shearing strength of 
one rivet in single shear =iVX>SXo+nXsXa 

Z)= strength of plate between rivet holes in the second row, plus the shearing 
Btrength of one rivet in single shear in the outer row = (P — 2d) tXTS 
-\-nXsXa 




Fig. 27 Example of Butt and Double Strap 
Joint, Double-Biveted 



F= strength of plate between rivet holes in the second row, plus the crushing 
strength of butt strap in front of one rivet in the outer row = (P — 2d) i 
XTS+dXbXc 

F= crushing strength of plate in front of two rivets, plus the crushing strength 
of butt strap in front of one livet =NXdXtXc+nXdXbXc 

G= crushing strength of plate in front of two rivets, plus the shearing strength 
of one rivet m single shear =A^Xc^XiXc+^XsXa 

£f= strength of butt straps between rivet holes in the inner row = (P — 2d) 2b 

X TS. This method of failure is not possible for thicknesses of butt straps 

required by these Rules and the computation need only be made for old 

boilers in which thin butt straps have been used. For this reason this 

method of failure will not be considered in other joints. 

Divide B, C, D, E, F,GoxH (whichever is the least) by A, and the quotient will 



100 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.B. 



be the efficiency of a butt and double strap joint, double-riveted, as shown in 
Fig. 27. 

r^ = 55,000 lb. per sq. in. a=0.6013 sq. in. 

^ t= ^ in. =0.375 in. 5=44,000 lb. per sq. in. 

' h= ^ in. =0.3125 in. ^=88,000 lb. per sq. in, 

P=47^in.=4.875in. c =95,000 lb. per sq. in, 

d= 7^ in. =0.875 in. 

Number of rivets in single shear in a unit length of joint = 1. 
Number of rivets in double shear in a unit length of joint =2. 




Fig. 28 Example of Butt and Double Strap Joint, Triple-Riveted 



A =4.875X0.375X55,000 = 100,547 

B = (4.875—0.875) 0.375 X 55,000 = 82,500 

C =2 X88,000 X0.6013 + 1 X44,000 X0.6013 = 132,286 

Z) = (4.875— 2X0.875)0.375X55,000+1X44,000X0.6013=90,910 

.£; = (4.875— 2X0.875)0.375X55,000+0.875X0.3125X95,000=90,429 

F =2 X0.875 X0.375 X95,000+0.875 XO.3125 X95,000 = 88,320 

0=2X0.875X0.375X95,000+1X44,000X0.6013=88,800 

82,500 (B) 



100,547 {A) 



=0.820 = efficiency of joint 



414 Example: Butt and double strap joint, triple-riveted. 
A = strength of solid plate = PXtXTS 

J5 = strength of plate between rivet holes in the outer row = (P — d) tXTS 
C= shearing strength of four rivets in double shear, plus the shearing strength 

of one rivet in single shear=i\rx>SXa+nXsXa 
Z)= strength of plate between rivet holes in the second row, plus the shearing 

strength of one rivet in single shear in the outer row = (P— 2d) txTS 

•jrnXsXa 



APPENDIX 101 

£^ = strength of plate between rivet holes in the second row, plus the cnishin^ 
strength of butt strap in front of one rivet in the outer row = (P — 2d) t 
XTS+dXbXc 

F = crushing strength of plate in front of four rivets, plus the crushing strength 
of butt strap in front of one rivet =NXdXtXc+nXdXbXc 

G^ = crushing strength of plate in front of four rivets, plus the shearing strength 
of one rivet in single shear =NXdXtXc-\-nXsXa 

Divide B, C, Z), E\ F or G (whichever is the least) by A, and the quotient will 
be the efficiency of a butt and double strap joint, triple-riveted, as shown in Fig. 28. 

TaS =55,000 lb. per sq. in. a =0.5185 sq. in. 

t= ^ in. =0.375 in. s =44,000 lb. per sq. in. 

6= ^ in. =0.3125 in. ^=88,000 lb. per sq. in. 

P=6K in. =6.5 in. c =95,000 lb. per sq. in. 
d= if in. =0.8125 in. 

Number of rivets in single shear in a unit length of joint = 1. 
Number of rivets in double shear in a unit length of joint =4. 

A =6.5X0.375X55,000 = 134,062 

B = (6.5—0.8125) 0.375X55,000 = 117,304 

€ =4 X88,000 XO.5185+1 X44,000XO.5185 =205,326 

D = (6.5—2 X0.8125) 0.375 X 55,000+1 X44,000X0.5185 = 123,360 

E = (6.5—2 X0.8125) 0.375 X 55,000 +0.8125 X0.3125 X95,000 = 124,667 

F = 4 X0.8125X0.375 X95,000+l X0.8125 X0.3125 X95,000 = 139,902 

G =4 X0.8125 X0.375 X95,000+l X44,000X0.5185 = 138,595 

117,304(5) 

: — =0.875 = efficiency of jomt 

134,062 (A) ^ 

415 Example: Butt and double strap joint, quadruple-riveted. 

A = strength of solid plate = PXtXTS 

B = strength of plate between rivet holes in the outer row = (P — d) I X TS 

C = shearing strength of eight rivets in double shear, plus the shearing strength 
of three rivets in single shear =iVX>SXa+nXsX<x 

D = strength of plate between rivet holes in the second row, plus the shearing 
strength of one rivet in single shear in the outer row = (P — 2d) tXTS 
+lXsXa 

£" = strength of plate between rivet holes in the third row, plus the shearing 
strength of two rivets in the second row in single shear and one rivet in 
single shear in the outer row = (P — 4.d) t X TS-\-nXsXa 

P-- strength of plate between rivet holes in the second row, plus the crushing 
strength of butt strap in front of one rivet in the outer row = (P — 2d) t 
XTS-]-dXbXc 



102 



ESPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



G = strength of plate between rivet holes in the third row, plus the crushing 

strength of butt strap in front of two rivets in the second row and one 

rivet in the outer rov/ = (P — 4d) tXTS+nXdXbXc 
ff= crushing strength of plate in front of eight rivets, plus the crushing strength 

of butt strap in front of three vwets—NXdXtXc-{-nXdXbXc 
/= crushing strength of plate in front of eight rivets, plus the shearing strength 

of two rivets in the second row and one rivet in the outer row, in single 

shear =NXdXtXc+nXsXa 
Divide B, C, D, E, F, G, H ov I (whichever is the least) by Af and the quotient 
will be the efficiency of a butt and double strap joint quadruple-riveted, as shown 
in Fig. 29. 




Fig. 29 Example of Butt and Double Strap Joint, Quadeuple-Eiveted 



T>S=55,0001b. persq. in. 

i= 3^ in. =0.5 in. 

h= a^ in. =0.4375 in. 
P = 15in. 
d= H in. =0.9375 in. 



a =0.6903 sq. in. 
5=44,000 lb. per sq. in. 
iS=88,0001b. persq. in. 
c= 95,000 lb. per sq. in. 



Number of rivets in single shear in a unit length of joint =3. 

Number of rivets in double shear in a unit length of joint = 8. 
.A = 15 XO.5 X55,000 = 412,500 
.B = (15— 0.9375) 0.5X55,000 = 386,718 
C = 8 X88,000 X 0.6903 +3 X44,000 X0.6903 = 577,000 
I) = (15— 2X0.9375) 0.5X55,000+1X44,000X0.6903=391,310 
i7 = (15— 4X0.9375) 0.5X55,000+3X44,000X0.6903=400,494 
F = (15—2 X0.9375) 0.5 X 55,000 +0.9375 XO.4375 X95,000 = 399,902 
(? = (15—4X0.9375) 0.5X55,000+3X0.9375X0.4375X95,000 = 426,269 
£? =8X0.9375X0.5X95,000+3X0.9375X0.4375X95,000 = 473,145 
/=8X0.9375X0.5X95,000+3X44,000X0.6903 =447,369 



386,718 jB) 
412,500 {A) 



=0.937 = efficiency of joint 



APPENDIX 



103 



416 Figs. 30 and 31 illustrate other joints that may be used 
in which eccentric stresses are avoided. The butt and double strap 
joint with straps of equal width shown in Fig, 30 may be so de- 
signed that it will have an efficiencj^ of from 82 to 84 per cent and 
the saw-tooth joint shown in Fig. 31 so that it will have an 
efficiency of from 92 to 04 per cent. 




Fig. 30 Illustration of Butt and Double Strap Joint with Straps of 

Equal Width 




ITlG. 31 Illustration of Butt and Double Strap Joint of the Saw-Tooth 

Type 



104 



REPORT OF BOILER CODE COMMITTEE, Alkl.SOC.M.E. 



Braced and Stated Surfaces 

417 Tlie allowable loads based on the net cross-sectional areas of 
staybolts with V-threads, are computed from the following formulae. 
The use of Whitworth threads with other pitches is permissible. 

The formula for the diameter of a staybolt at the bottom of a 
T-thread is: 

D— (P X l.'i'32) = d 
where 

D = diameter of staj^bolt over the threads, in. 
P = pitch of threads, in. 

d = diameter of staybolt at bottom of threads, in. 
1.73i2 = a constant 

When U. .S. threads are used, the formula becomes 

D~ (PX l.'^3,2 X 0.75) = d 

Tables 11 and 12 give the allowable loads on net cross-sectional 
areas for staybolts with Y-threads, having 12 and 10 threads per inch. 



TABLE 11. ALLOWABLE LOADS ON STAYBOLTS WITH V-THREADS, 12 THREADS 

PER INCH 





Diameter at 


Net Cross- 


Allowable Load 


of 


Bottom of 


Sectional Area 


at 7500 Lb, 


Staybolts, In. 


Thread, 


(at Bottom of 


Stress, per 


In. 


Thread) , Sq. In. 


Sq. In. 


H 


0.7500 


0.6057 


0.288 


2160 


H 


0.8125 


0.6682 


0.351 


2632 


Vs 


0.8750 


0.7307 


0.419 


3142 


if 


0.9375 


0.7932 


0.494 


3705 


1 


1.0000 


0.8557 


0.575 


4312 


li^ 


1.0625 


0.9182 


0.662 


4965 


13^ 


1.1250 


0.9807 


0.755 


5662 


lA 


1 . 1875 


1.0432 


0.855 


6412 


1>4 


1.2500 


1.1057 


0.960 


7200 


lA 


1.3125 


1 . 1682 


1.072 


8040 


i^ 


1 . 3750 


1.2307 


1.190 


8925 


lA 


1.4375 


1.2932 


1.313 


9849 


IH 


1.5000 


1.3557 


1.444 


10830 



APPENDIX 



10; 



TAB-LE 12. ALLOWABLE LOADS ON STAYBOLTS WITH V-THREADS. 10 THREADS 

PER INCH 



Outside Diameter 

of 

Staybolts, In. 


Diameter at 

Bottom 

of Thread, 

In. 


Net Cross- 
Sectional Area 
(at Bottom of 
Thread), Sq. In. 


Allowable Load 

at 7500 Lb. 

Stress per 

Sq. In. 


1ft 

lA 

1^ 

1^ 


1.2500 
1.3125 
1 . 3750 
1.4375 
1 . 5000 
1.5625 
1.6250 


1.0768 
1 . 1393 
1.2018 
1.2643 
1.3268 
1 . 3893 
1.4518 


0.911 
1.019 
1.134 
1.255 
1.382 
1.515 
1.655 


6832 

7642 

8505 

9412 

10365 

11362 

12412 



418 Table 13 shows the allowable loads on net cross-sectional 
areas of round stays or braces. 

TABLE 13. ALLOWABLE LOADS ON ROUND BRACES OR STAY RODS 



Minimum 

Diameter 

of Circular 

Stay, In. 


Net 

Cross-sectional 

Area of Stay, 

in Sq. In. 


Allowable Stress, in Lb. per Sq. In., Net Cross-sectional 
Area 


6000 8500 


9500 


Allowable Load, in Lb., on Net Cross-sectional Area 


1 1.0000 
1^ 1.0625 
lyi 1.1250 
lA 1.1875 
l}i 1.2500 
lA 1.3125 
m 1.3750 
lA 1.4375 
m 1.5000 
1^ 1.5625 
IH 1.6250 
IH 1.6875 
IM 1.7500 
IH 1.8125 
V/s 1.8750 
IH 1.9375 

2 2.0000 
2}4 2.1250 
2H 2.2500 
2% 2.3750 
2}4 2.5000 
2H 2.6250 
2M 2.7500 
2H 2.8750 

3 3.0000 


0.7854 
0.8866 
0.9940 
1 . 1075 
1.2272 
1.3530 
1.4849 
1.6230 
1.7671 
1.9175 
2.0739 
2.2365 
2.4053 
2.5802 
2.7612 
2.9483 
3.1416 
3.5466 
3.9761 
4.4301 
4.9087 
5.4119 
5.9396 
6.4918 
7.0686 


4712 

5320 

5964 

6645 

7363 

8118 

8909 

9738 

10603 

11505 

12443 

13419 

14432 

15481 

16567 

17690 

18850 

21280 

23857 

26580 

29452 

32471 

35638 

38951 

42412 


6676 
7536 
8449 
9414 
10431 
115C1 
12622 
13796 
15020 
16298 
17628 
19010 
20445 
21932 
23470 
25061 
26704 
30147 
33797 
37656 
41724 
46001 
50487 
55181 
60083 


7462 
8423 
9443 
10521 
11658 
12854 
14107 
15419 
16787 
18216 
19702 
21247 
22852 
24512 
26231 
28009 
29845 
33693 
37773 
42086 
46632 
51413 
56426 
61673 
67152 



419 Table 14 gives the net areas of segments of heads for use in 
computing stays. 



106 



REPORT OF BOILER CODE COMMITTEE, AM.SOCM.E. 



TABLE 14 NET AREAS OF SEGMENTS OF HEADS WHERE d AS GIVEN IN 
PARS. 214 AND 217, IS EQUAL TO 3 IN. 



Height 




Diameter of Boiler, I 


D. 










from 














1 












Tubes 
to 


24 


30 


36 


42 


48 


54 60 


66 


72 


78 


84 


90 


96 


Shell, 


















, In. 


\ 


Area to be stayed, Sq. 


In. 










8 


28 


33 


37 


40 


43 


/ 


17 51 


53 


55 


58 


60 


63 


63 


8J^ 


35 


41 


46 


51 


55 


^ 


59 63 


66 


70 


74 


76 


80 


82 


9 


42 


49 


56 


62 


67 




12 76 


82 


86 


90 


92 


95 


98 


^Vi 


50 


58 


66 


70 


80 


{ 


?6 91 


96 


101 


105 


111 


116 


119 


10 


57 


68 


77 


85 


93 


\ 


)9 106 


112 


117 


123 


129 


132 


137 


103^ 


66 


78 


89 


98 


107 


1 


14 123 


131 


135 


142 


147 


153 


160 


11 


74 


88 


100 


111 


121 


1; 


10 138 


147 


155 


161 


169 


174 


183 


11J4 


83 


99 


112 


124 


137 


1^ 


16 156 


165 


173 


181 


189 


196 


204 


12 


91 


109 


125 


139 


151 


1< 


33 174 


184 


194 


203 


213 


219 


230 


12>^ 




120 


138 


153 


167 


W 


10 193 


204 


216 


224 


234 


243 


252 


13 




132 


151 


1G8 


183 


l\ 


)7 211 


224 


235 


247 


256 


267 


279 


133^ 




143 


164 


183 


200 


2 


16 230 


246 


258 


270 


282 


293 


302 


14 




155 


178 


199 


217 


2: 


J4 250 


266 


280 


294 


305 


319 


331 


i^Vi 




167 


192 


215 


235 


2. 


54 271 


287 


303 


318 


333 


345 


360 


15 




178 


206 


231 


252 


2' 


IZ 291 


309 


326 


343 


357 


372 


386 


15^ 






220 


247 


271 


2< 


n 312 


332 


350 


368 


382 


400 


417 


16 








235 


263 


289 


3 


12 334 


355 


374 


394 


411 


423 


443 


16>^ 








249 


281 


308 


3; 


J2 357 


380 


399 


420 


43j6 


457 


475 


17 








264 


297 


326 


3. 


53 378 


402 


425 


447 


467 


486 


502 


1714 










314 


345 


3' 


r4 400 


426 


449 


471 


494 


516 


536 


18 












331 


365 


3< 


)6 424 


450 


476 


500 


520 


543 


564 


183^ 












349 


384 


4 


L7 448 


476 


501 


526 


552 


577 


598 


19 


.... 










366 


404 


4; 


J9 470 


500 


529 


555 


580 


604 


631 


19^ 












384 


424 


4( 


51 496 


528 


558 


584 


613 


641 


663 


20 












401 


444 


45 


?3 519 


552 


583 


613 


642 


667 


699 


203^ 














464 


5( 


)5 543 


578 


613 


643 


675 


706 


729 


21 
















485 


5i 


28 668 


604 


640 


673 


705 


733 


766 


213^ 
















505 


5. 


51 594 


632 


669 


703 


739 


766 


797 


22 
















626 


5' 


r4 618 


658 


697 


734 


769 


800 


835 


22^ 


















61 


)7 643 


687 


726 


765 


800 


835 


867 


23 


















. 6i 


20 668 


713 


754 


796 


830 


869 


906 


23>i 


















6^ 


12 695 


740 


784 


827 


866 


904 


945 


24 


















6( 


57 719 


768 


814 


859 


897 


939 


978 


243^ 


















. 65 


?9 745 


797 


843 


892 


934 


975 


1018 


25 


















. 7] 


L4 771 


825 


875 


922 


966 


1010 


1051 


253^ 


















. T. 


57 798 


855 


907 


956 


1003 


1047 


1092 


26 


















. 7( 


51 824 


882 


936 


987 


1035 


1083 


1126 


2^14 




















.. 850 


909 


968 


1024 


1073 


1120 


1167 


27 




.... 
















... 877 


939 


998 


1053 


1106 


1157 


1202 


2734 




.... 
















... 904 


968 


1030 


1089 


1145 


1195 


1243 


28 




















... 930 


997 


1060 


1120 


1177 


1232 


1279 


2834 






















1028 


1092 


1157 


1211 


1270 


1321 


29 
























1056 


1123 


1187 


1248 


1305 


1360 


2Q]4 
























1084 


1155 


1221 


1284 


1347 


1400 


30 
























1115 


1187 


1255 


1321 


1382 


1442 


3034 


























1218 


1290 


1358 


1424 


1480 


31 




























1252 


1324 


1394 


1459 


1523 


31^ 




























1286 


1359 


1433 


1496 


1561 


32 




























1317 


1394 


1467 


1538 


1605 


3234 






























1430 


1508 


1575 


1650 


33 






























1465 


1542 


1617 


1687 


3314 






























1500 


1578 


1655 


1733 


34 




























1536 


1617 


1695 


1770 


3434. 






























1654 


1735 


1816 


35 






























1692 


1775 


1856 


35^., 
































1810 


1900 


36 






























1857 


1941 


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1984 


37 






























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108 report op boiler code committee, am.soc.m.e. 

Safety Valves 

420 Method of Computing Discharge Capacity, The required 
discharge capacity of a safety valve or valves for a boiler may be 
based either on the heat units in the fuel consumed or on the 
amount of steam generated. 

The number of heat units in the fuel that each safety valve will 
handle per hour, for valves of the ordinary types in which the 
discharge capacity is proportioned to the lift, may be obtained as 
follows : 

V — 161,000 X P X ^ X -^ for Bevel Seats at 45 deg. 

V = 227,500 XPXDXL for Flat Seats 
U = 72,500 XPXA for seats of any angle 

The amount of steam that a valve will discharge in pounds per 
hour, may be found as follows: 

W = 110 X P X ^ X i^ for Bevel Seats at 45 deg. 
W = 155 XPXDXL for Flat Seats 
W = 50 X -P X ^ for seats of any angle 
where 

U = Number of heat units in the fuel that a safety valve 

will handle per hour, B.t.u. 
W = Quantity of steam that a safety valve will handle per 

hour, lb. 
P =: Absolute boiler pressure = gage pressure + 14.7 lb. 

per sq. in. ' 

D = Inside diameter of valve seat, in. 
L = Vertical lift of valve disk, measured with 3 per cent 

excess pressure, in. 
A — Believing area in sq. in. =: 3.1416 X D X LX sine of 

seat angle. 

Method of Checking the Safety Valve Capacity by Measuring 
THE Maximum Amount of Fuel that can be Burned 

421 The maximum quantity of fuel C that can be burned per 
hour at the time of maximum forcing is determined by a test. The 
maximum number of heat units per hour, or C X -^ is then deter- 



APPENDIX 109 

mined, using the values of H given in Par. 426. The weight of 
steam generated per hour is found by the formula : 

(7 X -g X 0.75 
1 100 
where 

W = weight of steam generated per hour, lb. 
C = total weight or volume burned per hour at time of 

maximum forcing, lb. or cu. ft. 
H = heat of combustion of fuel, B.t.u. per lb. or per cu. 
ft. (see Par. 426). 
The sum of the safety valve capacities marked on the valves 
shall be equal to or greater than W. 

422 Example 1 : A boiler at the time of maximum forcing uses 
2150 lb. of Illinois coal per hour of 12,100 B.t.u. per lb. Boiler 
pressure, 225 lb. per sq. in gage. 

CXSz=: 2150 X 12,100 = 26,015,000 
W=CXHX 0.75^1100 = 17,740 
A 3}^ in. bevel-seated valve with 0.11 in. lift would discharge 
in heat units 

V = 161,000 X 239.7 X 31/2 X 0.11 
= 14,858,000 
and in weight of steam 

W = 110 X 239.7 X 31/2 X 0.11 
= 10,150 
From which it can be seen that either method indicates that 
two such valves will give the proper relieving capacity. 

423 Example 2: "Wood shavings of heat of combustion of 6400 
B.t.u. per lb. are burned under a boiler at the maximum rate of 
2000 lb. per hour. Boiler pressure, 100 lb. per sq. in. gage. 

CXE[ = 2000 X 6400 == 12,800,000 

W = CXSX 0.75-^-1100 = 8730 
A bevel-seated 3^^ in. valve is marked by the manufacturer 0.11 
in. lift and discharge capacity for 100 lb. pressure = 4840 lb. ; hence 
two such valves would be required. 

424 Example 3: An oil-fired boiler at maximum forcing uses 
1000 lb. of crude oil (Texas) per hour. Boiler pressure, 275 lb. per 
sq. in. gage. 

CXH = 1000 X 18,500 = 18,500,000 
W — CXSX 0.75-T-llOO = 12,620 



110 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

A bevel-seated 2^ in. valve is marked by the manufacturer 0.08 
in. lift and discharge capacity for 275 lb. pressure = 6350 lb. ; 
hence two such valves would be required. 



425 Example 4 : A boiler fired with natural gas consumes 3000 
cu. ft. per hour. The working pressure is 150 lb. per sq. in. gage. 

CXS = 3000 X 960 = 2,880,000 

W = CXSX 0.75-f-llOO = 1960 

A bevel-seated 2 in. valve is marked by the manufacturer 0.07 
in. lift and discharge capacity for 150 lb. pressure = 2500 lb. ; 
hence one such valve would be required. 



426 For the purpose of cheeking the safety valve capacity as 
described in Par. 421, the following values of heats of combustion 
of various fuels may be used: ^ 

H = B.t.u. 
per lb. 

Semi-bituminous coal 14,500 

Anthracite o 13,700 

Screenings 12,500 

Coke o 13,500 

Wood, hard or soft, kiln dried. . o ..... = 7,700 

Wood, hard or soft, air dried, .... ....... . » . . o 6,200 

Wood shavings , .. , « 6,400 

Peat, air dried, 25 per cent moisture , . » , , . . , 7,500 

Lignite 10,000 

Kerosene » 20,000 

Petroleum, crude oil, Penn 20,700 

Petroleum, crude oil, Texas » 18,500 

H=B.t.n. 
per cu. ft. 

Natural gas 960 

Blast-furnace gas 100 

Producer gas 150 

Water gas, uncarbureted • • • 290 



TABLE 15 DISCHARGE CAPACITIES FOR DIRECT SPRING-LOADED POP SAFETY VALVES. 

WITH 45 DEG. BEVEL SEATS 



Gage 
Pres., 
Lb. ppr 
Sq. In. 




Diameter, 1 In. 


Diameter, IJ^ In. 


Diameter, \]/2 In. 


Min, 


Int. 


Max. 


Min. 


Int. 


Max. 


Min. 


Int. 


Max. 


15 


Lift, in. . . . 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


95,500 


191,000 


238,900 


179,200 


238,800 


293,500 


214,900 


358,300 


429,900 


Lb. hr 


65 


131 


163 


122 


163 


203 


146 


245 


293 


25 


Lift, in 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


127,700 


255,400 


319,300 


239,500 


319,300 


399,100 


287,400 


478.900 


574,700 


Lb. hr 


87 


174 


218 


164 


218 


272 


196 


326 


392 


50 


Lift, in. . . . 


0.02 


0.04 


0.05 


0,03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


208,200 


416,400 


520,400 


390,300 


520,400 


650.500 


468,300 


780.600 


936,600 


Lb. hr 


142 


284 


354 


266 


354 


444 


320 


532 


639 


75 


Lift, in. . . . 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


288,600 


577,200 


721,400 


541,100 


721,400 


901,800 


649,-300 


1.082,000 


1.299,000 


Lb. hr 


197 


393 


492 


369 


492 


615 


443 


738 


88C 


100 


Lift, in ... . 


0.02 


0.04 


0.05 


0.03 


0.04 


05 


0.03 


0.05 


0.06 


CH 


369,000 


738,000 


922,500 


691,900 


922,500 


1,153,000 


830,300 


1,384,000 


1,661,000 


Lb. hr 


252 


503 


629 


472 


629 


786 


566 


944 


1133 


125 


Lift, in. . . . 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


449,400 


898,900 


1,124,000 


842,700 


1,124,000 


1,404,000 


1,011,000 


1,685,000 


2,022,000 


Lb. hr 


307 


613 


767 


575 


767 


957 


689 


1149 


1379 


150 


Lift, in. . , . 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


06 


CH.. 


529,900 


1,060,000 


1,325,000 


993,500 


1,325,000 


1,656,000 


1,192,000 


1,987,000 


2,384,000 


Lb. hr 


362 


723 


904 


677 


904 


1129 


813 


1355 


1625 


175 


Lift, in 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


06 


CH....... 


610,300 


1,221,000 


1,526,000 


1,144,000 


1,526,000 


1,907,000 


1,373,000 


2,280,000 


2,746,000 


Lb. hr 


416 


833 


1040 


780 


1040 
0.04 


1301 
0.05 


936 


1561 


1872 


200 


Lift, in 


0.02 


0.04 


0.05 


0.03 


0.03 


0.05 


0.06 


CH 


690,700 


1,381,000 


1,727,000 


1,295,000 


1,727,000 


2,158,000 


1,554,000 


2,590,000 


3.108.000 


Lb. hr 


471 


941 


1178 


883 


117S 


1472 


1060 


1766 


21 le 


225 


Lift, in 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


771,100 


1,542,000 


1,928,000 


1,446,000 


1,928,000 


2,410,000 


1,735,000 


2,892,000 


3,470.000 


Lb. hr. . , . 


526 


1052 


1315 


986 


1315 


1643 


1183 


1972 


236C 


250 


Lift, in. . .1 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH. ..... 


851,600 


1,703,000 


2,129,000 


1,597,000 


2,129,000 


2,661,000 


1,916,000 


3,193,000 


3.832,000 


Lb. hr. . . . 


581 


1161 


1451 


1089 


1451 


1814 


1307 


2177 


2613 


275 


Lift, in 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


932,000 


1,864,000 


2,330,000 


1,748,000 


2,330,000 


2,913,000 


2,097.000 


3,495,000 


4,194,000 


Lb. hr 


635 


1271 


1589 


1192 


1589 


1986 


1430 


2383 


2860 


300 


Lift, in. . . 


0.02 


0.04 


0.05 


0.03 


0.04 


0.05 


0.03 


0.05 


0.06 


CH 


1,024,000 


2,048,000 


2,531,000 


1,898,000 


2,531,000 


3,164,000 


2,278,000 


3,797,000 


4,556,000 


Lb. hr 


698 


1397 


1746 


1294) 


1726 


2157 


1553 


2589 


3107 



The Discharge capacity of a Flat Seat Valve of a given diameter with a given lift may be obtained by multiplying 
the discharge capacity given in the Table for a 45 deg. bevel seat valve of same diameter and same lift, by 1.4. 

Ill' 



TABLE 15 (Continued) DISCHARGE CAPACITIES FOR DIRECT SPRING-LOADED POP 
SAFETY VALVES, WITH 45 DEG. BEVEL SEATS 



Gage 

Pree., 

Lb. per 

Sq. In. 




Diameter, 2 In. 


Diameter, 23^ In, 


Diameter, 3 In. 


Min. 


Int. 


Max. 


Min. 


Int. 


Max. 


Min. 


Int. 


Max. 


15 


Lift, in. . . . 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


382,200 


673,300 


668,900 


477,700 


716,600 


955,500 


716,600 


1,147,000 


1,433,000 


Lb. hr 


261 


3.91 


456 


326 


488 


651 


489 


782 


977 


25 


Lift, in 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


510,900 


766,300 


894,000 


638,500 


957,900 


1,277,000 


957,900 


1,533,000 


1,916,000 


Lb. hr 


349 


523 


610 


435 


653 


871 


653 


1046 


1307 


50 


Lift, in. . . 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


832,600 


1,249,000 


1,457,000 


1,041,000 


1,561,000 


2,081,000 


1,561,000 


2,498,000 


3,122,000 


Lb. hr. . , . 


6CS 


851 
0.06 


994 
0.07 


710 
0.04 


1064 


1419 


1064 


1703 


2120 


75 


Lift, in , . . 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


1,154,000 


1,731,000 


2,020,000 


1,443,000 


2,164,000 


2,886,000 


2,164,000 


3,463,000 


4,329,000 


Lb. hr. . . 


787 


1181 


1377 

0.07 


984 
04 


1475 


1968 


1475 


2361 


2951 


100 


Lift, in . . . 


0.04 


0.06 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


1,476,000 


2,214,C0C 


2,583,000 


1,845,000 


2,708,000 


3,690,000 


2,768,000 


4,428,000 


5,535,000 


Lb.hr 


1007 


1510 


1701 
"^.07 


1258 
0.04 


1887 
O.OG 


2516 


1887 


3019 


3774 


125 


Lift, in. . . . 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


1,795,000 


2,693,000 


3,146,000 


2,247,000 


3,371,000 


4,494,000 


3,371,000 


5,393,000 


6,741,000 


Lb. hr 


1224 


1836 


2145 


1532 


2299 


3064 


2299 


3677 


4596 


150 


Lift, in. . . . 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


2,109,000 


3,179,000 


3,709,000 


2,649,000 


3,974,000 


5.299,000 


3,974,000 


6,358,000 


7,948,000 


Lb. hr 


1438 


2158 


2529 


1806 


2710 


3613 


2710 


4335 


5419 


175 


Lift, in 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


2,441.000 


3,662,000 


4,272,000 


3,051,000 


4,577,000 


6,103,000 


4,577,000 


7,323,000 


9,154,000 


Lb. hr 


1664 


2497 


2913 
0.07 


2081 


3121 


4161 


3121 


4993 


6242 


200 


Lift, in. . . . 


0.04 


0.06 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


2,763,000 


4,144,000 


4,835,000 


3,454,000 


5,180,000 


6,907,000 


5,180,000 


8,289,000 


10,361,000 


Lb.hr 


1884 


2826 


3296 


2354 


3532 


4709 


3532 


5651 


7064 


225 


Lift, in. . . . 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


3,085,000 


4,626,000 


5,398,000 


3,856,000 


5,784,000 


7,711,000 


5,784,000 


9,254,000 


11,567,000 


Lb. hr 


2104 


3154 


3680 
0.07 


2629 
0.04 


3944 


5258 


3944 


6310 


7890 


250 


Lift, in. .. . 


0.04 


0.06 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


3,406,000 


5,109,000 


5,961,000 


4,258,000 


6,387,000 


8,516,000 


6,387,000 


10,219,000 


12,774,000 


Lb. hr 


2322 


3484 


4064 


2903 


4355 


5807 


4355 


6968 


8708 


275 


Lift, in 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


3,728,000 


5,592,000 


6,524,000 


4,660,000 


6,990,000 


9,320,000 


6,990,000 


11,180,000 


13,980,000 


Lb. hr 


2542 


3813 


4448 


3177 


4760 


6355 


4766 


7620 


9533 


300 


Lift, in. . . . 


0.04 


0.06 


0.07 


0.04 


0.06 


0.08 


0.05 


0.08 


0.10 


CH 


4,050,000 


6,075,000 


7,087,000 


5,062,000 


7,593,000 


10,124,000 7,593,000 


12,149,000 


15,186,000 


Lb. hr. .. 


2762 


4143 


4832 


3452 


5177 


6903 5177 


8280 


10,358 



The Discharge capacity of a Flat Seat 
the discharge capacity giveu m the Table 



Valve of a given diameter with a given lift may be obtained by multiplying 
for a 45 deg. bevel seat valve of same diameter and same lift, by 1.4. 

This table ia concluded on the follounng pagt% 

112 . 



TABLE 15 (Concluded) DISCHARGE CAPACITIES FOR DIRECT SPRING-LOADED POP SAFETY 

VALVES, WITH 45 DEG. BEVEL SEATS 



Gage 
Pres., 




Diameter, 3H In. 


Diameter, 4 In. 


Diameter, 4 K In. 


Sq. In. 


Min. 


Int. 


Max. 


Min. 


Int. 


Max. 


Min. 


Int. 


Max. 




Lift, in 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


15 


CE 


1,003,000 


1,505,000 


1,839,000 


1,338,000 


1,911,000 


2,293,000 


1,720,000 


2,365,000 


2,795,000 


Lb. hr 


684 


1026 


1254 


912 


1303 


1564 


1173 


1613 


1906 


25 


Lift, in. . . . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


1,341,000 


2,012,000 


2,459,000 


1,788,000 


2,554,000 


3,065,000 


2,299,000 


3,161,000 


3,736.000 


Lb. hr 


914 


1372 


1676 


1219 


1742 


2090 


1568 


2156 


2547 


Lift, in. . . . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


SO 


CH 


2,186,000 


3,278,000 


4,007,000 


2,914,000 


4,163,000 


4,996,000 


3,747,000 


5,152,000 


6,088,000 


Lb. hr 


1490 


2235 


2732 


1987 


2839 


3406 


2555 


3513 


4151 


75 


Lift, in. . . . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


3,030,000 


4,545,000 


5,555,000 


4,040,000 


5,772,000 


6,926,000 


5,194,000 


7,142,000 


8,441,000 


Lb.hr 


2066 


3099 


3788 


2754 


3935 


4722 


3542 


4870 


5756 


100 
125 


Lift, in. . . . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


3,875,000 


5,812,000 


7,103,000 


5,166,000 


7,380,000 


8,856,000 


6,642,000 


9,133,000 


10,793,000 


Lb. hr 


2642 


3963 


4843 


3522 


5032 


6038 


4529 


6227 


V 7358 


Lift, in. . . . 


0.06 


0.09 


0.11 


07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH , 


4,719,000 


7,079,000 


8,652,000 


6,292,000 


8,988,000 


10,786,000 


8,089,000 


11,123,000 


13,146,000 


Lb.hr 


3218 


4826 


5899 


4290 


6128 


7354 


5516 


7583 


8963 


150 


Lift, in 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


5,564,000 


8,345,000 


10,199,000 


7,418.000 


10,597,000 


12,717,000 


9,537,000 


13,114,000 


15,498.000 


Lb. hr 


3794 


5690 


6954 


5058 


7226 


8670 


6503 


8940 


10566 


175 


Lift, in, . , . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


6,408,000 


9,612,000 


11,748,000 


8,544,000 


12,206,000 


14,647,000 


10,985,000 


15,105,000 


17,851,000 


Lb. hr 


4369 


6553 


8010 


5824 


8320 


9984 


7490 


10298 


12173 


200 


Lift, in . , . . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


7,253,000 


10,879,000 


13,296,000 


9,670,000 


13,814,000 


16,580,000 


12,433,000 


17,095,000 


20,204,000 


Lb. hr. . . 


4946 


7418 


9068 


6593 


9420 


11305 


8475 


11655 


13773 


225 


Lift, in . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


8,097,000 


12,146,000 


14,845,000 


10,796,000 


15,423,000 


18,507,000 


13,881,000 


19,086,000 


22,556,000 


Lb.hr . ,. 


5521 


8280 


10120 


7361 


10514 


12616 


9465 


13013 


15383 


250 


Lift, in. . . . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH . 


8,942,000 


13,412,000 


16,393,000 


11,922,000 


17,031,000 


20,438,000 


15,328,000 


21,076,000 


24,908,000 


Lb. hr. . . 


6097 


9143 


11175 


8130 


11614 


13938 


10448 


14366 


16980 


275 


Lift, in 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH...... . 


9,786,000 


14,679,000 


17,941,000 


13,048,000 


18,640,000 


22,368,000 


16,776,000 


23,067,000 


27,261,000 


Lb. hr. ,. . 


6672 


10005 


12233 


8895 


12707 


15248 


11438 


15728 


18585 


300 


Lift, in. , . . 


0.06 


0.09 


0.11 


0.07 


0.10 


0.12 


0.08 


0.11 


0.13 


CH 


10,630,00C 


15,946,000 


19,489,000 


14,174,000 


20,249.000 


24,298,000 


18,224,000 


25,058,000 


29,614,000 


Lb. hr . 


7248 


10875 


13290 


9668 


13807 


16568 


12428 


17088 


20195 



The DischarKe capacity of a Flat Seat Valve of a given diameter with a given lift may be obtained by multiplying 
the discharge capacity given in the Table for a 45 deg. bevel seat valve of same diameter and same lift, by 1.4. 

113 



114 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 



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116 



REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.B. 




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appendix 117 

Automatic Water Gages 

427. Automatic shut-off valves on water gages, if permitted to 
bo used, shall conform to the following requirements : 

a. Cheek valves in upper and lower fittings must be of the solid 
non-ferrous ball type to avoid corrosion and the necessity for 
guides. 

&. Ball check valves in upper and lower fittings must open by 
gravity, and the lower ball check valve must rise vertically to 
its seat. 

c. The check balls must not be smaller than % in. diameter, and 
the diameter of the circle of contact with the seat must not 
be greater than 2/3 of the diameter of the check ball. The 
space around each ball must not be less than % in., and the 
travel movement from the normal resting place to the seat 
must not be less than 14 i^- 

d. The ball seat in the upper fitting must be a fiat seat with 
•either a square or hexagonal opening, or otherwise arranged so 

that the steam passage can never be completely closed by this 
valve. 

e. The shut-off valve in the upper fitting must have a projection 
which holds the ball at least % in. away from its seat when 
the shut-off valve is closed. 

/. The balls must be accessible for inspection. Means must be 
provided for removal and inspection of the lower ball check 
valve, while the boiler is under steam pressure. 



Fusible Plugs 

428 Fusible plugs, if used, shall be filled with tin with a melt- 
ing point between 400 and 500 deg. fahr., and shall be renewed 
once each year. 

429 The least diameter of fusible metal shall be not less than % 
in., except for maximum allowable working pressures of over 175 lb. 
per sq. in. or when it is necessary to place a fusible plug in a tube, 
in which case the least diameter of fusible metal shall be not less 
than % in. 



118 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

430 Each boiler may have one or more fusible plugs, located as 
follows : 

a In Horizontal Return-Tubular Boilers — in the rear head, 
not less than 2 in. above the upper row of tubes, the meas- 
urement to be taken from the line of the upper surface of 
tubes to the center of the plug, and projecting through 
the sheet not less than 1 in. 

i In Horizontal Flue Boilers — in the rear head, on a line with 
the highest part of the boiler exposed to the products of 
combustion, and projecting through the sheet not less than 
lin. 

c In Traction, Portable or Stationary Boilers of the Loco- 
motive Type or Star Water Tube Boilers — in the highest 
part of the crown sheet, and projecting through the sheet 
not less than 1 in. 

d In Vertical Fire-tube Boilers — ^in an outside tube, not less 
than one-third the length of the tube above the lower tube 
sheet. 

e In Vertical Fire-tube Boilers, 'Corliss Type — ^in a tube, not 
less than one-third the length of the tube above the lower 
tube sheet. 

/ In Vertical Submerged-Tube Boilers— in the upper tube 
sheet, and projecting through the sheet not less than 1 in. 

g In Water-tube Boilers, Horizontal Drums, Babcock & Wilcox 
Type — in the upper drum, not less than 6 in. above the 
bottom of the drum, over the first pass of the products 
of combustion, and projecting through the sheet not less 
than 1 in. 

7^ In Stirling Boilers, Standard Type — in the front side of 
the middle drum, not less than 4 in. above the bottom of 
the drum, and projecting through the sheet not less than 
1 in. 

i In Stirling Boilers, Superheater Type— in the front drum, 
not less than 6 in. above the bottom of the drum, exposed 
to the products of combustion, and projecting through 
the sheet not less than 1 in. 

j In Water-tube Boilers, Heine Type— in the front course of 
the drum, not less than 6 in. above the bottom of the 
drum, and projecting through the sheet not less than 1 in. 

k In Robb-Mumford Boilers, Standard Type— in the bottom 



rf^ 



MANUFACTURERS' DATA REPORT— ALL. TYPES OF BOILERS 

As Required by the Provisions of the A.S.M.E. Code Rules 



1. Mnnufs. ;Liired by 

2. Manufactured for 



.No, of drums. . 



CarLon . . 
Uanganesi 

PLosplioru 
Sulpliur . 

Thicknesa 



Furoaco Sheet; 



Has material used in boiler been 
checked with mill test reports. . , . 
Material of: 

Rivets Braces, . 

(Slcelorlrou) 



Staybolta . . . , 
Longitudinal e 



Pitch X X in. Effic, 



lleaders of W. T. 

. % I 11, boilers : Material 

ts) (Cast or wrougbt, i 



(lougiiuUinally diagonally) 
Heads of 
. drums : Form , 



(For V, T. boUcra only) (Over UireaiLs) 
Hoar sq. in Pront sq, in, Ecar. 



IS. Openings: No. . 
i Built for 



work, pressure 

; and tliat all details of material and construction and workmanship on this boiler conform to 



Fig. CI. Front 



' Data. Sueet JTorm i 



CERTIFICATE OF BOII.EU SHOP INSPECTION 



Insurance Company 'a Serial Number 

BOILER "WORKS OP at 

I, the undersigned, holding a certificate of competency as an inspector of steam boilers in THE STATE 

OP , and employed by the 

of , inspected internally and externally, the boiler specified in this report, on 

10 , and certify that the statements made on this report are correct, corresponding with tlio 

mill teat reports of material as fnrnishcd by the builders, and measurements made of the boiler tvhcn completed; and 
that this boiler is constructed in accordance with the A.S.M.E. Rules. 



/nspcc(or o/ Boilers for 



Beab Side of Data Sh. 



APPENDIX 119 

of the steam and water drum, 24 in. from the center of 
the rear neck, and projecting through the sheet not less 
than 1 in. 

I In Water-tube J3oi!ers, Almy Type— in a tube or fitting ex- 
posed to the products of combustion. 

m In Vertical Boilers, Climax or Hazelton Type — in a tube or 
center drum not less than one-half the height of the shell, 
measuring from the lowest circumferential seam. 

n In Cahall Vertical Water-tube Boilers — in the inner sheet 
of the top drum, not less than 6 in. above the upper tube 
sheet, and projecting through the sheet not less than 1 in. 

In Wickes Vertical Water-tube Boilers — in the shell of the 
top drum and not less liian 6 in. above the upper tube 
sheet, and projecting through the sheet not less than 1 in. ; 
60 located as to be at the front of the boiler and exposed to 
the first pass of the products of combustion. 

p In Scotch Marine Type Boilers — in the combustion chamber 
top, and projecting through the sheet not less than 1 in. 

q In Dry Back ;Scotch Type Boilers — in the rear head, not less 
than 2 in. above the upper row of tubes, and projecting 
through the sheet not less than 1 in. 

r In Economic Type Boilers — ^in the rear head, above the upper 
TOW of tubes. 

is In Cast-iron (Sectional Heating Boilers — in a section over 
and in direct contact with the products of combustion in 
the primary combustion chamber. 

i In Water-tube Boilers, Worthingtor T^pe — in the front side 
of the steam and water drum, not less than 4 in. above the 
bottom of the drum, and projecting through the sheet not 
less than 1 in. 

u Fire Engine Boilers are not usually supplied with fusible 
plugs. Unless special provision is made to keep the 
water above the firebox crown sheet other than by the 
natural level, the lowest permissible water level shall 
be at least 3 in. above the top of the firebox crown sheet. 

V For other types and new designs, fusible plugs shall be 
placed at the lowest permissible water level, in the 
direct path of the products of combustion, as near the 
primary combustion chamber as possible. 



120 report of boiler code committee, am.soc.m.e. 

Recommendations for Repairs when Made by Welding and 

Reinforcing by the Electric, Oxy-Acetylene, or 

Other Processes 

From General Rules and Regulations Prescribed hy the Board of 
Supervising Inspectors j U. S, Steamboat-Inspection Service 

All calking edges on internally fired boilers may be reinforced 
by these processes. 

Calking edges of the shells of externally fired boilers, above the 
fire line only, may be reinforced. 

Cracks extending from edge of lap to rivet, except on seams 
below the fire line in externally fired boilers, may be welded. 

Cracks not exceeding 30 in. in length in back connection sheets, 
wrapper sheets, bottoms of combustion chambers, heads, and other 
stayed surfaces may be repaired by welding. 

Where cracks are repaired by welding, holes shall be drilled 
entirely through the plate at each extreme end of the crack, except 
in small cracks from rivet to calking edge. 

Circumferential or lengthwise cracks not exceeding 16 in. in 
length in plain or corrugated furnaces may be welded. 

Where plates in back sheets of back connections, wrapper sheets 
of sides and bottoms of back connections of any boilers, side sheets 
and legs of furnaces and bottoms of furnaces of fire-box boilers, 
and other stayed surfaces are reduced in thickness not exceeding 
40 per cent of the original thickness, they may be reinforced, such 
reinforcing not to exceed an area of 200 sq. in. in any one plate. 

When such reinforcing extends over stays and braces, such stays 
and braces shall come completely through the reinforcing so as to 
be plainly visible to the inspectors. 

When the corroded portion of stayed or riveted surfaces of the 
back sheets or wrapper sheets or bottoms of back connections of any 
boilers, or side sheets and bottom sheets of furnaces or legs of fire- 
box boilers exceeds 300 sq. in., the same may be repaired by the 
removal of the corroded portion and the replacement thereof by a 
new piece of plate, the edges of the new plate being welded in 
position. 

Staybolts, braces, or rivets shall pass through the body of the 
new plate as before, the area of the new piece not to exceed 24 by 
24 in., or 30 in. in any one direction, the welded edges to be V'd 
or beveled along the joint prior to welding. 



APPENDIX 121 

Where plates of shells and other parts of internally fired boilers 
subject to tensile strain are reduced in thickness by corrosion not 
to exceed 25 per cent of the original thickness, they may be rein- 
forced, such reinforcing not to exceed an area of 200 sq. in. 

Where calking edges and laps have been reinforced, local 
inspectors shall require the rivets to be cut out and redriven if they 
[find by inspection that it is necessary. 

No welding shall be allowed in cracks in the shell plates or 
other plates subject to tensile strain. 

Cracks extending through rivet holes in single-riveted or 
double-riveted seams in stayed surfaces of back connections of any 
boilers or side sheets of legs or bottoms of fire-box boilers which are 
stayed surfaces may be welded up to a length of 6 ft. exclusive of 
rivet holes. 

Where cracks extend through rivet holes in stayed surfaces, the 
piece extending from the rivet to the edge of the lap may be removed 
where convenient to do so, and the place where the piece has been 
removed may be replaced by being built up and reinforced by 
either of these processes. 

Where leaks develop around staybolts and the staybolts are 
otherwise intact, the nuts may be removed from the ends of the 
staybolts, and the staybolts may be welded into the shell by welding 
a beveled collar or ring around the staybolt. The width and depth 
of such collar shall equal one-half of the diameter of the staybolt. 
In all such cases of applying welding rings or collars around stay- 
bolts, the material shall be hammered while in a glowing state as 
it is applied. 

In all cases where metal is deposited on stayed surfaces, the 
operator shall hammer, when practicable, the deposited metal while 
it is in a glowing state. 

Cracks in wrought-iron or wrought-steel headers, and cracks or 
sand holes in cast-steel, semisteel, ferrosteel, malleable-iron or cast- 
iron headers, manifolds, crosses, tees, and ells may be repaired by 
welding cracks or flowing metal into sand holes. Such repaired 
material other than headers and manifolds shall be subjected to a 
hydrostatic test of three and one-half times the working pressure 
after such repairs are made. Reinforcing by building up of any 
of the above-mentioned articles other than headers shall not be 
allowed. 



,!7,!,?,f^'^RY OF CONGRESS 



029 827 665 3 



122 REPORT OF BOILER CODE COMMITTEE, AM.SOC.M.E. 

When crown-bar bolts have deteriorated or wasted away at top 
of combustion chamber under the crown bars, such deterioration 
not to exceed 25 per cent of the original diameter of the bolt, 
such bolts may be built up or reinforced by any process of auto- 
genous welding. 

Where tube sheets of boilers have deteriorated not to exceed 25 
per cent of their original thickness, or where cracks have developed 
in tube sheets, the same may be reinforced and repaired by any 
process of autogenous welding, and the beading on the end of tubes 
may be welded to the tube sheets by the same process. 



LIBRARY OF CONGRESS 



029 827 665 3 ^ 



LIBRARY OF CONGRESS 



I II III I 



029 827 665 3 



